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..926a863114598e70e92b319878dcf16f0121a837 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 +2894,34 @@ 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;
+
+  const gfx::Range requested_range(range);
+  if (requested_range.is_reversed())
+    return nil;
+
+  gfx::Range expected_range;
+  base::string16 expected_text;
+
+  if (!renderWidgetHostView_->composition_range().is_empty()) {
+    expected_text = markedText_;
+    expected_range = renderWidgetHostView_->composition_range();
+  } else {
+    expected_text = renderWidgetHostView_->selection_text();
+    size_t offset = renderWidgetHostView_->selection_text_offset();
+    expected_range = gfx::Range(offset, offset + expected_text.size());
+  }
+
+  if (!expected_range.Contains(requested_range))
+    return nil;
+
+  std::string result_text;
+  if (!base::UTF16ToUTF8(

[yukawa, 2015/08/21 06:54:50]

(optional) Perhaps we can use something here to avoid UTF16 -> UTF8 -> USString
conversions?

https://code.google.com/p/chromium/codesearch#chromium/src/base/strings/sys_s...

[Shu Chen, 2015/08/21 07:11:54]

Done.

+      expected_text.data() + requested_range.start() - expected_range.start(),
+      requested_range.length(), &result_text)) {
+    return nil;
+  }
+  NSString *nstr = [[NSString alloc] initWithUTF8String:result_text.c_str()];
+  return [[NSAttributedString alloc] initWithString:nstr];
 }
 
 - (NSInteger)conversationIdentifier {