Do not calculate composition bounds until IME requests.

content/renderer/render_widget.cc

Index: content/renderer/render_widget.cc
diff --git a/content/renderer/render_widget.cc b/content/renderer/render_widget.cc
index 8a771c9ee7bfb6aad650489888624ebfcc58670b..31bfc66a3cd8d7669b91a00a4f27aad7950e7dc6 100644
--- a/content/renderer/render_widget.cc
+++ b/content/renderer/render_widget.cc
@@ -246,6 +246,7 @@ RenderWidget::RenderWidget(CompositorDependencies* compositor_deps,
       text_input_mode_(ui::TEXT_INPUT_MODE_DEFAULT),
       text_input_flags_(0),
       can_compose_inline_(true),
+      composition_range_(gfx::Range::InvalidRange()),
       popup_type_(popup_type),
       pending_window_rect_count_(0),
       screen_info_(screen_info),
@@ -253,6 +254,7 @@ RenderWidget::RenderWidget(CompositorDependencies* compositor_deps,
 #if defined(OS_ANDROID)
       text_field_is_dirty_(false),
 #endif
+      monitor_composition_info_(false),
       popup_origin_scale_for_emulation_(0.f),
       frame_swap_message_queue_(new FrameSwapMessageQueue()),
       resizing_mode_selector_(new ResizingModeSelector()),
@@ -498,6 +500,8 @@ bool RenderWidget::OnMessageReceived(const IPC::Message& message) {
     IPC_MESSAGE_HANDLER(InputMsg_ImeEventAck, OnImeEventAck)
     IPC_MESSAGE_HANDLER(InputMsg_RequestTextInputStateUpdate,
                         OnRequestTextInputStateUpdate)
+    IPC_MESSAGE_HANDLER(InputMsg_RequestCompositionUpdate,
+                        OnRequestCompositionUpdate)
     IPC_MESSAGE_HANDLER(ViewMsg_ShowImeIfNeeded, OnShowImeIfNeeded)
 #endif
     IPC_MESSAGE_HANDLER(ViewMsg_HandleCompositorProto, OnHandleCompositorProto)
@@ -899,6 +903,13 @@ void RenderWidget::UpdateTextInputState(ShowIme show_ime,
   }
 
   ui::TextInputType new_type = GetTextInputType();
+#if !defined(OS_ANDROID)

[aelias_OOO_until_Jul13, 2016/07/26 19:26:02]

Sorry, I realize you're just following the conventions in this file, but putting
one-liner behavior changes behind platform ifdefs is a bad practice that often
causes pain and confusion later, and I am aiming to slowly remove all cases of
that.  The RequestCompositionUpdate IPC mechanism is powerful enough for all
platforms, so it should not be needed to fork the logic here.

It would be almost equivalent to have
RenderWidgetHostView{Aura,Mac}::TextInputStateChanged implementation that sends
a InputMsg_RequestCompositionUpdate, so can you do that?  (If there is a timing
problem with that, then feel free to widen it to another condition, but I just
would like to avoid an ifdef in this file and have the behavior differ only in
the actual browser-side platform files.)

[Seigo Nonaka, 2016/07/28 09:10:59]

Sure, for Mac OSX, it is not a monitor implementation, so I fixed only for Aura.

+  // Monitor the composition information during the focused node is text input
+  // node. On Android, monitor_composition_info_ is controlled by
+  // RequestCompositionUpdate message.
+  monitor_composition_info_ = new_type != ui::TEXT_INPUT_TYPE_NONE;
+#endif
+
   if (IsDateTimeInput(new_type))
     return;  // Not considered as a text input field in WebKit/Chromium.
 
@@ -1358,7 +1369,7 @@ void RenderWidget::OnImeSetComposition(
     // sure we are in a consistent state.
     Send(new InputHostMsg_ImeCancelComposition(routing_id()));
   }
-  UpdateCompositionInfo(true);
+  UpdateCompositionInfo(false /* not an immediate request */);
 }
 
 void RenderWidget::OnImeConfirmComposition(const base::string16& text,
@@ -1387,7 +1398,7 @@ void RenderWidget::OnImeConfirmComposition(const base::string16& text,
   else
     webwidget_->confirmComposition(WebWidget::DoNotKeepSelection);
   input_handler_->set_handling_input_event(false);
-  UpdateCompositionInfo(true);
+  UpdateCompositionInfo(false /* not an immediate request */);
 }
 
 void RenderWidget::OnDeviceScaleFactorChanged() {
@@ -1472,19 +1483,26 @@ ui::TextInputType RenderWidget::GetTextInputType() {
   return ui::TEXT_INPUT_TYPE_NONE;
 }
 
-void RenderWidget::UpdateCompositionInfo(bool should_update_range) {
+void RenderWidget::UpdateCompositionInfo(bool immediate_request) {
+  if (!monitor_composition_info_ && !immediate_request)
+    return;  // Do not calculate composition info if not requested.
+
   TRACE_EVENT0("renderer", "RenderWidget::UpdateCompositionInfo");
-  gfx::Range range = gfx::Range();
-  if (should_update_range) {
-    GetCompositionRange(&range);
+  gfx::Range range;
+  std::vector<gfx::Rect> character_bounds;
+
+  if (GetTextInputType() == ui::TEXT_INPUT_TYPE_NONE) {
+    // Composition information is only available on editable node.
+    range = gfx::Range::InvalidRange();
   } else {
-    range = composition_range_;
+    GetCompositionRange(&range);
+    GetCompositionCharacterBounds(&character_bounds);
   }
-  std::vector<gfx::Rect> character_bounds;
-  GetCompositionCharacterBounds(&character_bounds);
 
-  if (!ShouldUpdateCompositionInfo(range, character_bounds))
+  if (!immediate_request &&
+      !ShouldUpdateCompositionInfo(range, character_bounds)) {
     return;
+  }
   composition_character_bounds_ = character_bounds;
   composition_range_ = range;
   Send(new InputHostMsg_ImeCompositionRangeChanged(
@@ -1541,6 +1559,14 @@ void RenderWidget::OnRequestTextInputStateUpdate() {
   UpdateSelectionBounds();
   UpdateTextInputState(ShowIme::HIDE_IME, ChangeSource::FROM_IME);
 }
+
+void RenderWidget::OnRequestCompositionUpdate(bool immediate_request,
+                                              bool monitor_request) {
+  monitor_composition_info_ = monitor_request;
+  if (!immediate_request)
+    return;
+  UpdateCompositionInfo(true /* immediate request */);
+}
 #endif
 
 bool RenderWidget::ShouldHandleImeEvent() {
@@ -1734,7 +1760,7 @@ void RenderWidget::UpdateSelectionBounds() {
     }
   }
 
-  UpdateCompositionInfo(false);
+  UpdateCompositionInfo(false /* not an immediate request */);
 }
 
 void RenderWidget::SetDeviceColorProfileForTesting(
@@ -1879,7 +1905,7 @@ void RenderWidget::resetInputMethod() {
       Send(new InputHostMsg_ImeCancelComposition(routing_id()));
   }
 
-  UpdateCompositionInfo(true);
+  UpdateCompositionInfo(false /* not an immediate request */);
 }
 
 #if defined(OS_ANDROID)