Avoid sync IPCs for firstRectForCharacterRange/attributedSubstringForProposedRange.

content/browser/renderer_host/render_widget_host_view_mac.mm

Index: content/browser/renderer_host/render_widget_host_view_mac.mm
diff --git a/content/browser/renderer_host/render_widget_host_view_mac.mm b/content/browser/renderer_host/render_widget_host_view_mac.mm
index 66f1c31650f7799701f8aba763b515e7c340aaeb..fd786f1da8f5d99679ad499ea65b652fac9dbdb9 100644
--- a/content/browser/renderer_host/render_widget_host_view_mac.mm
+++ b/content/browser/renderer_host/render_widget_host_view_mac.mm
@@ -1225,6 +1225,7 @@ void RenderWidgetHostViewMac::SelectionBoundsChanged(
     const ViewHostMsg_SelectionBounds_Params& params) {
   if (params.anchor_rect == params.focus_rect)
     caret_rect_ = params.anchor_rect;
+  first_selection_rect_ = params.anchor_rect;
 }
 
 void RenderWidgetHostViewMac::SetShowingContextMenu(bool showing) {
@@ -1453,6 +1454,12 @@ bool RenderWidgetHostViewMac::GetCachedFirstRectForCharacterRange(
     return true;
   }
 
+  if (composition_range_.is_empty()) {
+    *actual_range = selection_range_.ToNSRange();
+    *rect = NSRectFromCGRect(first_selection_rect_.ToCGRect());
+    return true;
+  }
+
   const gfx::Range request_range_in_composition =
       ConvertCharacterRangeToCompositionRange(gfx::Range(range));
   if (request_range_in_composition == gfx::Range::InvalidRange())
@@ -2887,10 +2894,26 @@ extern NSString *NSTextInputReplacementRangeAttributeName;
   // TODO(thakis): Pipe |actualRange| through TextInputClientMac machinery.
   if (actualRange)
     *actualRange = range;
-  NSAttributedString* str =
-      TextInputClientMac::GetInstance()->GetAttributedSubstringFromRange(
-          renderWidgetHostView_->render_widget_host_, range);
-  return str;
+  gfx::Range expected_range;
+  std::wstring expected_text;  // Using wide string for string truncation.
+  std::string result_text("");
+
+  if (!renderWidgetHostView_->composition_range().is_empty()) {
+    expected_range = renderWidgetHostView_->composition_range();
+    expected_text = base::UTF16ToWide(markedText_);
+  } else if (!renderWidgetHostView_->selection_range().is_empty()) {

[yukawa, 2015/08/20 09:14:49]

I think we can take advantage of |RenderWidgetHostViewBase::selection_text_| and
|RenderWidgetHostViewBase::selection_text_offset_| here.  In order to support
IMR_RECONVERTSTRING on Windows, |RenderWidgetHostViewBase::selection_text_|
generally contains preceding and trailing characters around the actual text
selection, which means that we can support a bit wider range than the selected
range.

[Shu Chen, 2015/08/21 03:13:11]

Done.

+    expected_range = renderWidgetHostView_->selection_range();
+    expected_text = base::UTF8ToWide(renderWidgetHostView_->selected_text());
+  }
+
+  if (expected_range.start() <= range.location &&

[yukawa, 2015/08/20 09:14:49]

Don't we need to return nil when there is no intersection between
|expected_range| and |range|?

Also don't we need to update |range| (or |actualRange|) with |expected_range|?

https://developer.apple.com/library/mac/documentation/Cocoa/Reference/NSTextI...:

[Shu Chen, 2015/08/21 03:13:11]

Done. I think we don't need to update |actualRange| because we always return the
text according to |range|.

+      expected_range.end() >= range.location + range.length) {
+    result_text = base::WideToUTF8(expected_text.substr(
+        range.location - expected_range.start(), range.length));
+  }
+
+  NSString *nstr = [[NSString alloc] initWithUTF8String:result_text.c_str()];
+  return [[NSAttributedString alloc] initWithString:nstr];
 }
 
 - (NSInteger)conversationIdentifier {