[unseasoned-pdf] Add unit tests for DocumentLoadFailed().

Add unit tests for PdfViewPluginBase::DocumentLoadFailed() and set enum
class `DocumentLoadState` public so that it can be used for testing.

Bug: 1218534
Change-Id: I81eef5f441b9eed3dfe15884278545d9db278adf
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2982662
Reviewed-by: Lei Zhang <thestig@chromium.org>
Commit-Queue: Hui Yingst <nigi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#895433}

pdf/pdf_view_plugin_base.h

@@ -60,6 +60,12 @@ class PdfViewPluginBase : public PDFEngine::Client,
  public:
   using PDFEngine::Client::ScheduleTaskOnMainThread;
 
+  enum class DocumentLoadState {
+    kLoading = 0,
+    kComplete,
+    kFailed,
+  };
+
   // Must match `SaveRequestType` in chrome/browser/resources/pdf/constants.js.
   enum class SaveRequestType {
     kAnnotation = 0,
@@ -145,12 +151,6 @@ class PdfViewPluginBase : public PDFEngine::Client,
     kLoaded,   // Fully loaded.
   };
 
-  enum class DocumentLoadState {
-    kLoading = 0,
-    kComplete,
-    kFailed,
-  };
-
   struct BackgroundPart {
     gfx::Rect location;
     uint32_t color;

pdf/pdf_view_plugin_base_unittest.cc

@@ -66,10 +66,12 @@ class TestPDFiumEngine : public PDFiumEngine {
 class FakePdfViewPluginBase : public PdfViewPluginBase {
  public:
   // Public for testing.
+  using PdfViewPluginBase::document_load_state;
   using PdfViewPluginBase::edit_mode;
   using PdfViewPluginBase::full_frame;
   using PdfViewPluginBase::HandleMessage;
   using PdfViewPluginBase::InitializeEngine;
+  using PdfViewPluginBase::set_document_load_state;
   using PdfViewPluginBase::set_full_frame;
 
   MOCK_METHOD(bool, Confirm, (const std::string&), (override));
@@ -234,6 +236,41 @@ TEST_F(PdfViewPluginBaseTest, CreateUrlLoaderWithoutFullFrame) {
   EXPECT_FALSE(fake_plugin_.GetDidCallStartLoadingForTesting());
 }
 
+TEST_F(PdfViewPluginBaseTest, DocumentLoadFailedWithNotifiedRenderFrame) {
+  // Notify the render frame about document loading.
+  fake_plugin_.set_full_frame(true);
+  ASSERT_TRUE(fake_plugin_.full_frame());
+  fake_plugin_.CreateUrlLoader();
+
+  ASSERT_EQ(PdfViewPluginBase::DocumentLoadState::kLoading,
+            fake_plugin_.document_load_state());
+  EXPECT_TRUE(fake_plugin_.GetDidCallStartLoadingForTesting());
+
+  EXPECT_CALL(fake_plugin_, UserMetricsRecordAction("PDF.LoadFailure"));
+  EXPECT_CALL(fake_plugin_, PluginDidStopLoading());
+
+  fake_plugin_.DocumentLoadFailed();
+  EXPECT_EQ(PdfViewPluginBase::DocumentLoadState::kFailed,
+            fake_plugin_.document_load_state());
+  EXPECT_FALSE(fake_plugin_.GetDidCallStartLoadingForTesting());
+}
+
+TEST_F(PdfViewPluginBaseTest, DocumentLoadFailedWithoutNotifiedRenderFrame) {
+  // The render frame has never been notified about document loading before.
+  ASSERT_FALSE(fake_plugin_.full_frame());
+  EXPECT_FALSE(fake_plugin_.GetDidCallStartLoadingForTesting());
+
+  ASSERT_EQ(PdfViewPluginBase::DocumentLoadState::kLoading,
+            fake_plugin_.document_load_state());
+  EXPECT_CALL(fake_plugin_, UserMetricsRecordAction("PDF.LoadFailure"));
+  EXPECT_CALL(fake_plugin_, PluginDidStopLoading()).Times(0);
+
+  fake_plugin_.DocumentLoadFailed();
+  EXPECT_EQ(PdfViewPluginBase::DocumentLoadState::kFailed,
+            fake_plugin_.document_load_state());
+  EXPECT_FALSE(fake_plugin_.GetDidCallStartLoadingForTesting());
+}
+
 TEST_F(PdfViewPluginBaseTest, DocumentHasUnsupportedFeatureInFullFrame) {
   fake_plugin_.set_full_frame(true);
   ASSERT_TRUE(fake_plugin_.full_frame());