Revert "Revert "[PDF] Avoid sending unnecessary SetPluginCanSave messages""

This reverts commit 73dcfc0ec3.

Reason for revert:
LUCI Bisection has identified this change as the culprit of a build failure. See the analysis: https://ci.chromium.org/ui/p/chromium/bisection/compile-analysis/b/8731798983355037505

Sample failed build: https://ci.chromium.org/b/8731798983355037505

If this is a false positive, please report it at http://b.corp.google.com/createIssue?component=1199205&description=Analysis%3A+https%3A%2F%2Fchromium-review.googlesource.com%2Fc%2Fchromium%2Fsrc%2F%2B%2F6006316&format=PLAIN&priority=P3&title=Wrongly+blamed+https%3A%2F%2Fci.chromium.org%2Fui%2Fp%2Fchromium%2Fbisection%2Fcompile-analysis%2Fb%2F8731798983355037505&type=BUG

Original change's description:
> Revert "[PDF] Avoid sending unnecessary SetPluginCanSave messages"
>
> This reverts commit 1b98c1c3c1.
>
> Reason for revert: Causing failure on linux-chromeos-chrome
> https://ci.chromium.org/ui/p/chrome/builders/ci/linux-chromeos-chrome/46306/overview
>
> Original change's description:
> > [PDF] Avoid sending unnecessary SetPluginCanSave messages
> >
> > SetPluginCanSave is a renderer-to-browser message that PdfViewWebPlugin
> > sends to let the browser know that the plugin will handle the save.
> > PdfViewWebPlugin can send the message multiple times, even if the
> > browser already knows if the plugin will handle the save. Avoid
> > redundant calls.
> >
> > Change-Id: Ice4dbc0d97fd70a48d7314adf7dc50f9a5a2dabf
> > Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6001192
> > Reviewed-by: Lei Zhang <thestig@chromium.org>
> > Commit-Queue: Andy Phan <andyphan@chromium.org>
> > Code-Coverage: findit-for-me@appspot.gserviceaccount.com <findit-for-me@appspot.gserviceaccount.com>
> > Cr-Commit-Position: refs/heads/main@{#1380560}
>
> Change-Id: Ie8f963e9d763f5c830ee1a57dc3a200df045534b
> No-Presubmit: true
> No-Tree-Checks: true
> No-Try: true
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6006316
> Owners-Override: Di Zhang <dizhangg@google.com>
> Commit-Queue: Di Zhang <dizhangg@chromium.org>
> Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
> Cr-Commit-Position: refs/heads/main@{#1380649}
>

Change-Id: I1af9a60d05ba4febe96df789843b1738b4270f6f
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6006340
Bot-Commit: luci-bisection@appspot.gserviceaccount.com <luci-bisection@appspot.gserviceaccount.com>
Commit-Queue: luci-bisection@appspot.gserviceaccount.com <luci-bisection@appspot.gserviceaccount.com>
Owners-Override: luci-bisection@appspot.gserviceaccount.com <luci-bisection@appspot.gserviceaccount.com>
Cr-Commit-Position: refs/heads/main@{#1380708}

pdf/pdf_view_web_plugin.cc

@@ -1380,7 +1380,7 @@ void PdfViewWebPlugin::SelectionChanged(const gfx::Rect& left,
 
 void PdfViewWebPlugin::EnteredEditMode() {
   edit_mode_ = true;
-  pdf_host_->SetPluginCanSave(true);
+  SetPluginCanSave(true);
 
   base::Value::Dict message;
   message.Set("type", "setIsEditing");
@@ -1690,17 +1690,19 @@ void PdfViewWebPlugin::HandleSaveMessage(const base::Value::Dict& message) {
 #if BUILDFLAG(ENABLE_INK)
       // In annotation mode, assume the user will make edits and prefer saving
       // using the plugin data.
-      pdf_host_->SetPluginCanSave(true);
+      SetPluginCanSave(true);
       SaveToBuffer(token);
       return;
 #else
       NOTREACHED();
 #endif  // BUILDFLAG(ENABLE_INK)
-    case SaveRequestType::kOriginal:
-      pdf_host_->SetPluginCanSave(false);
+    case SaveRequestType::kOriginal: {
+      const bool can_save = plugin_can_save_ || edit_mode_;
+      SetPluginCanSave(false);
       SaveToFile(token);
-      pdf_host_->SetPluginCanSave(edit_mode_);
+      SetPluginCanSave(can_save);
       return;
+    }
     case SaveRequestType::kEdited:
       SaveToBuffer(token);
       return;
@@ -1909,6 +1911,15 @@ void PdfViewWebPlugin::SaveToFile(const std::string& token) {
   pdf_host_->SaveUrlAs(GURL(url_), network::mojom::ReferrerPolicy::kDefault);
 }
 
+void PdfViewWebPlugin::SetPluginCanSave(bool can_save) {
+  if (plugin_can_save_ == can_save) {
+    return;
+  }
+
+  plugin_can_save_ = can_save;
+  pdf_host_->SetPluginCanSave(can_save);
+}
+
 void PdfViewWebPlugin::InvalidatePluginContainer() {
   client_->Invalidate();
 }

pdf/pdf_view_web_plugin.h

@@ -556,6 +556,11 @@ class PdfViewWebPlugin final : public PDFiumEngineClient,
   void SaveToBuffer(const std::string& token);
   void SaveToFile(const std::string& token);
 
+  // Sets whether the plugin can and should handle the save by using `pdf_host_`
+  // to notify the browser. Prevents duplicate notifications to the browser if
+  // the state has not changed.
+  void SetPluginCanSave(bool can_save);
+
   // Converts a scroll offset (which is relative to a UI direction-dependent
   // scroll origin) to a scroll position (which is always relative to the
   // top-left corner).
@@ -702,6 +707,8 @@ class PdfViewWebPlugin final : public PDFiumEngineClient,
 
   bool initialized_ = false;
 
+  bool plugin_can_save_ = false;
+
   blink::WebString selected_text_;
 
   std::unique_ptr<Client> const client_;

pdf/pdf_view_web_plugin_unittest.cc

@@ -2014,10 +2014,8 @@ TEST_F(PdfViewWebPluginSaveTest, OriginalInNonEditMode) {
   {
     InSequence pdf_host_sequence;
 
-    EXPECT_CALL(pdf_host_, SetPluginCanSave(false));
     EXPECT_CALL(pdf_host_, SaveUrlAs(GURL(kPdfUrl),
                                      network::mojom::ReferrerPolicy::kDefault));
-    EXPECT_CALL(pdf_host_, SetPluginCanSave(false));
   }
 
   ExpectUpdateTextInputState(blink::WebTextInputType::kWebTextInputTypeNone);