[unseasoned-viewer] Implement PdfViewWebPlugin::LinkAtPosition()

Similar to the Pepper implementation, return the link under the cursor,
which is updated upon PdfViewWebPlugin::HandleInputEvent(). Ignore the
position param of the method.

Meanwhile, bubble the `link_under_cursor_` state from PDFiumEngine up
to PdfViewPluginBase, since the state is more pertinent to the PDFEngine
client.

Bug: 1191817
Change-Id: I96671a7be79b0e03c6fa485f83b62bf1f9cfbc59
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2976675
Reviewed-by: Lei Zhang <thestig@chromium.org>
Commit-Queue: Daniel Hosseinian <dhoss@chromium.org>
Cr-Commit-Position: refs/heads/master@{#894530}

pdf/out_of_process_instance.cc

@@ -976,11 +976,6 @@ void OutOfProcessInstance::SetSelectedText(const std::string& selected_text) {
   pp::PDF::SetSelectedText(this, selected_text.c_str());
 }
 
-void OutOfProcessInstance::SetLinkUnderCursor(
-    const std::string& link_under_cursor) {
-  pp::PDF::SetLinkUnderCursor(this, link_under_cursor.c_str());
-}
-
 bool OutOfProcessInstance::IsValidLink(const std::string& url) {
   return pp::Var(url).is_string();
 }
@@ -1024,6 +1019,10 @@ void OutOfProcessInstance::SetContentRestrictions(int content_restrictions) {
   pp::PDF::SetContentRestriction(this, content_restrictions);
 }
 
+void OutOfProcessInstance::NotifyLinkUnderCursor() {
+  pp::PDF::SetLinkUnderCursor(this, link_under_cursor().c_str());
+}
+
 void OutOfProcessInstance::NotifySelectionChanged(const gfx::PointF& left,
                                                   int left_height,
                                                   const gfx::PointF& right,

pdf/out_of_process_instance.h

@@ -105,7 +105,6 @@ class OutOfProcessInstance : public PdfViewPluginBase,
                                                bool case_sensitive) override;
   pp::Instance* GetPluginInstance() override;
   void SetSelectedText(const std::string& selected_text) override;
-  void SetLinkUnderCursor(const std::string& link_under_cursor) override;
   bool IsValidLink(const std::string& url) override;
   std::unique_ptr<Graphics> CreatePaintGraphics(const gfx::Size& size) override;
   bool BindPaintGraphics(Graphics& graphics) override;
@@ -140,6 +139,7 @@ class OutOfProcessInstance : public PdfViewPluginBase,
   void PluginDidStartLoading() override;
   void PluginDidStopLoading() override;
   void InvokePrintDialog() override;
+  void NotifyLinkUnderCursor() override;
   void NotifySelectionChanged(const gfx::PointF& left,
                               int left_height,
                               const gfx::PointF& right,

pdf/pdf_view_plugin_base.cc

@@ -464,6 +464,15 @@ void PdfViewPluginBase::DocumentFocusChanged(bool document_has_focus) {
   SendMessage(std::move(message));
 }
 
+void PdfViewPluginBase::SetLinkUnderCursor(
+    const std::string& link_under_cursor) {
+  if (link_under_cursor_ == link_under_cursor)
+    return;
+
+  link_under_cursor_ = link_under_cursor;
+  NotifyLinkUnderCursor();
+}
+
 // TODO(crbug.com/1191817): Add tests for input events. Unit testing should be
 // feasible now that the Pepper dependency is removed for input events.
 bool PdfViewPluginBase::HandleInputEvent(const blink::WebInputEvent& event) {

pdf/pdf_view_plugin_base.h

@@ -107,6 +107,7 @@ class PdfViewPluginBase : public PDFEngine::Client,
   void SelectionChanged(const gfx::Rect& left, const gfx::Rect& right) override;
   void EnteredEditMode() override;
   void DocumentFocusChanged(bool document_has_focus) override;
+  void SetLinkUnderCursor(const std::string& link_under_cursor) override;
 
   // PaintManager::Client:
   void OnPaint(const std::vector<gfx::Rect>& paint_rects,
@@ -314,6 +315,11 @@ class PdfViewPluginBase : public PDFEngine::Client,
   // document.
   virtual void InvokePrintDialog() = 0;
 
+  // Notifies the embedder about a new link under the cursor.
+  // TODO(crbug.com/702993): This is only needed by `OutOfProcessInstance`.
+  // Remove this method when that class ceases to exist.
+  virtual void NotifyLinkUnderCursor() {}
+
   // Notifies the embedder of the top-left and bottom-right coordinates of the
   // current selection.
   virtual void NotifySelectionChanged(const gfx::PointF& left,
@@ -335,6 +341,8 @@ class PdfViewPluginBase : public PDFEngine::Client,
     cursor_type_ = cursor_type;
   }
 
+  const std::string& link_under_cursor() const { return link_under_cursor_; }
+
   bool full_frame() const { return full_frame_; }
   void set_full_frame(bool full_frame) { full_frame_ = full_frame; }
 
@@ -489,6 +497,9 @@ class PdfViewPluginBase : public PDFEngine::Client,
   // The current cursor type.
   ui::mojom::CursorType cursor_type_ = ui::mojom::CursorType::kPointer;
 
+  // The URL currently under the cursor.
+  std::string link_under_cursor_;
+
   // True if the plugin occupies the entire frame (not embedded).
   bool full_frame_ = false;
 

pdf/pdf_view_web_plugin.cc

@@ -71,6 +71,7 @@
 #include "ui/gfx/geometry/rect.h"
 #include "ui/gfx/range/range.h"
 #include "ui/gfx/skia_util.h"
+#include "url/gurl.h"
 #include "v8/include/v8.h"
 
 namespace chrome_pdf {
@@ -454,6 +455,11 @@ bool PdfViewWebPlugin::ExecuteEditCommand(const blink::WebString& name,
   return false;
 }
 
+blink::WebURL PdfViewWebPlugin::LinkAtPosition(
+    const gfx::Point& /*position*/) const {
+  return GURL(link_under_cursor());
+}
+
 bool PdfViewWebPlugin::StartFind(const blink::WebString& search_text,
                                  bool case_sensitive,
                                  int /*identifier*/) {
@@ -532,11 +538,6 @@ void PdfViewWebPlugin::SetSelectedText(const std::string& selected_text) {
       selected_text_, /*offset=*/0, gfx::Range(0, selected_text_.length()));
 }
 
-void PdfViewWebPlugin::SetLinkUnderCursor(
-    const std::string& link_under_cursor) {
-  NOTIMPLEMENTED();
-}
-
 bool PdfViewWebPlugin::IsValidLink(const std::string& url) {
   return base::Value(url).is_string();
 }

pdf/pdf_view_web_plugin.h

@@ -152,6 +152,7 @@ class PdfViewWebPlugin final : public PdfViewPluginBase,
   bool CanRedo() const override;
   bool ExecuteEditCommand(const blink::WebString& name,
                           const blink::WebString& value) override;
+  blink::WebURL LinkAtPosition(const gfx::Point& /*position*/) const override;
   bool StartFind(const blink::WebString& search_text,
                  bool case_sensitive,
                  int /*identifier*/) override;
@@ -176,7 +177,6 @@ class PdfViewWebPlugin final : public PdfViewPluginBase,
                                                bool case_sensitive) override;
   pp::Instance* GetPluginInstance() override;
   void SetSelectedText(const std::string& selected_text) override;
-  void SetLinkUnderCursor(const std::string& link_under_cursor) override;
   bool IsValidLink(const std::string& url) override;
   std::unique_ptr<Graphics> CreatePaintGraphics(const gfx::Size& size) override;
   bool BindPaintGraphics(Graphics& graphics) override;

pdf/pdfium/pdfium_engine.cc

@@ -4206,11 +4206,7 @@ void PDFiumEngine::UpdatePageCount() {
 #endif  // defined(PDF_ENABLE_XFA)
 
 void PDFiumEngine::UpdateLinkUnderCursor(const std::string& target_url) {
-  if (link_under_cursor_ == target_url)
-    return;
-
-  link_under_cursor_ = target_url;
-  client_->SetLinkUnderCursor(link_under_cursor_);
+  client_->SetLinkUnderCursor(target_url);
 }
 
 void PDFiumEngine::SetLinkUnderCursorForAnnotation(FPDF_ANNOTATION annot,

pdf/pdfium/pdfium_engine.h

@@ -776,9 +776,6 @@ class PDFiumEngine : public PDFEngine,
   // Whether to render PDF annotations.
   bool render_annots_ = true;
 
-  // The link currently under the cursor.
-  std::string link_under_cursor_;
-
   // Pending progressive paints.
   class ProgressivePaint {
    public:

pdf/pdfium/pdfium_engine_unittest.cc

@@ -541,6 +541,7 @@ class TabbingTestClient : public TestClient {
 
   // Mock PDFEngine::Client methods.
   MOCK_METHOD(void, DocumentFocusChanged, (bool), (override));
+  MOCK_METHOD(void, SetLinkUnderCursor, (const std::string&), (override));
 };
 
 class PDFiumEngineTabbingTest : public PDFiumTestBase {
@@ -579,10 +580,6 @@ class PDFiumEngineTabbingTest : public PDFiumTestBase {
     return engine->selection_.size();
   }
 
-  const std::string& GetLinkUnderCursor(PDFiumEngine* engine) {
-    return engine->link_under_cursor_;
-  }
-
   void ScrollFocusedAnnotationIntoView(PDFiumEngine* engine) {
     engine->ScrollFocusedAnnotationIntoView();
   }
@@ -603,28 +600,34 @@ TEST_F(PDFiumEngineTabbingTest, LinkUnderCursorTest) {
   scoped_feature_list.InitAndEnableFeature(
       chrome_pdf::features::kTabAcrossPDFAnnotations);
 
-  TestClient client;
+  TabbingTestClient client;
   std::unique_ptr<PDFiumEngine> engine =
       InitializeEngine(&client, FILE_PATH_LITERAL("annots.pdf"));
   ASSERT_TRUE(engine);
 
-  // Initial value of link under cursor.
-  EXPECT_EQ("", GetLinkUnderCursor(engine.get()));
+  // Tab to right before the first non-link annotation.
+  EXPECT_CALL(client, DocumentFocusChanged(true));
+  ASSERT_TRUE(HandleTabEvent(engine.get(), /*modifiers=*/0));
 
   // Tab through non-link annotations and validate link under cursor.
-  for (int i = 0; i < 4; i++) {
-    ASSERT_TRUE(HandleTabEvent(engine.get(), 0));
-    EXPECT_EQ("", GetLinkUnderCursor(engine.get()));
+  {
+    InSequence sequence;
+    EXPECT_CALL(client, SetLinkUnderCursor(""));
+    EXPECT_CALL(client, DocumentFocusChanged(false));
+    EXPECT_CALL(client, SetLinkUnderCursor("")).Times(2);
   }
 
+  for (int i = 0; i < 3; i++)
+    ASSERT_TRUE(HandleTabEvent(engine.get(), /*modifiers=*/0));
+
   // Tab to Link annotation.
-  ASSERT_TRUE(HandleTabEvent(engine.get(), 0));
-  EXPECT_EQ("https://www.google.com/", GetLinkUnderCursor(engine.get()));
+  EXPECT_CALL(client, SetLinkUnderCursor("https://www.google.com/"));
+  ASSERT_TRUE(HandleTabEvent(engine.get(), /*modifiers=*/0));
 
   // Tab to previous annotation.
+  EXPECT_CALL(client, SetLinkUnderCursor(""));
   ASSERT_TRUE(
       HandleTabEvent(engine.get(), blink::WebInputEvent::Modifiers::kShiftKey));
-  EXPECT_EQ("", GetLinkUnderCursor(engine.get()));
 }
 
 TEST_F(PDFiumEngineTabbingTest, TabbingSupportedAnnots) {
@@ -693,7 +696,7 @@ TEST_F(PDFiumEngineTabbingTest, TabbingForwardTest) {
    * ++ Page 2
    * ++++ Annotation
    */
-  TabbingTestClient client;
+  NiceMock<TabbingTestClient> client;
   std::unique_ptr<PDFiumEngine> engine = InitializeEngine(
       &client, FILE_PATH_LITERAL("annotation_form_fields.pdf"));
   ASSERT_TRUE(engine);
@@ -745,7 +748,7 @@ TEST_F(PDFiumEngineTabbingTest, TabbingBackwardTest) {
    * ++ Page 2
    * ++++ Annotation
    */
-  TabbingTestClient client;
+  NiceMock<TabbingTestClient> client;
   std::unique_ptr<PDFiumEngine> engine = InitializeEngine(
       &client, FILE_PATH_LITERAL("annotation_form_fields.pdf"));
   ASSERT_TRUE(engine);
@@ -852,7 +855,7 @@ TEST_F(PDFiumEngineTabbingTest, NoFocusableItemTabbingTest) {
    * ++ Page 1
    * ++ Page 2
    */
-  TabbingTestClient client;
+  NiceMock<TabbingTestClient> client;
   std::unique_ptr<PDFiumEngine> engine =
       InitializeEngine(&client, FILE_PATH_LITERAL("hello_world2.pdf"));
   ASSERT_TRUE(engine);
@@ -901,7 +904,7 @@ TEST_F(PDFiumEngineTabbingTest, RestoringDocumentFocusTest) {
    * ++ Page 2
    * ++++ Annotation
    */
-  TabbingTestClient client;
+  NiceMock<TabbingTestClient> client;
   std::unique_ptr<PDFiumEngine> engine = InitializeEngine(
       &client, FILE_PATH_LITERAL("annotation_form_fields.pdf"));
   ASSERT_TRUE(engine);
@@ -946,7 +949,7 @@ TEST_F(PDFiumEngineTabbingTest, RestoringAnnotFocusTest) {
    * ++ Page 2
    * ++++ Annotation
    */
-  TabbingTestClient client;
+  NiceMock<TabbingTestClient> client;
   std::unique_ptr<PDFiumEngine> engine = InitializeEngine(
       &client, FILE_PATH_LITERAL("annotation_form_fields.pdf"));
   ASSERT_TRUE(engine);