Expose whether a frame is focused to the browser process

content/browser/renderer_host/render_widget_host_impl.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/browser/renderer_host/render_widget_host_impl.h"
 
 #include <math.h>
 #include <set>
 #include <utility>
 
@@ skipping 166 matching lines @@
       ignore_input_events_(false),
       input_method_active_(false),
       text_direction_updated_(false),
       text_direction_(blink::WebTextDirectionLeftToRight),
       text_direction_canceled_(false),
       suppress_next_char_events_(false),
       pending_mouse_lock_request_(false),
       allow_privileged_mouse_lock_(false),
       has_touch_handler_(false),
       next_browser_snapshot_id_(1),
+      is_focused_(false),
       weak_factory_(this) {
   CHECK(delegate_);
   if (routing_id_ == MSG_ROUTING_NONE) {
     routing_id_ = process_->GetNextRoutingID();
     surface_id_ = GpuSurfaceTracker::Get()->AddSurfaceForRenderer(
         process_->GetID(),
         routing_id_);
   } else {
     // TODO(piman): This is a O(N) lookup, where we could forward the
     // information from the RenderWidgetHelper. The problem is that doing so
@@ skipping 446 matching lines @@
   Send(new ViewMsg_ChangeResizeRect(routing_id_, new_rect));
 }
 
 void RenderWidgetHostImpl::GotFocus() {
   Focus();
   if (delegate_)
     delegate_->RenderWidgetGotFocus(this);
 }
 
 void RenderWidgetHostImpl::Focus() {
+  is_focused_ = true;
   Send(new InputMsg_SetFocus(routing_id_, true));
 }
 
 void RenderWidgetHostImpl::Blur() {
+  is_focused_ = false;

[Charlie Reis, 2015/01/21 17:55:33]

Is this always called when another widget grabs focus, even when it's in the
renderer process?  I'm not sure if it's safe to maintain a focus state here.

[mlamouri (slow - plz ping), 2015/01/21 21:33:27]

As far as I can tell, yes. I also did a couple of tests with window.open().
Though, I might have missed some edge cases.

+
   // If there is a pending mouse lock request, we don't want to reject it at
   // this point. The user can switch focus back to this view and approve the
   // request later.
   if (IsMouseLocked())
     view_->UnlockMouse();
 
   if (touch_emulator_)
     touch_emulator_->CancelTouch();
 
   Send(new InputMsg_SetFocus(routing_id_, false));
 }
 
+bool RenderWidgetHostImpl::IsFocused() const {
+  return is_focused_;
+}
+
 void RenderWidgetHostImpl::LostCapture() {
   if (touch_emulator_)
     touch_emulator_->CancelTouch();
 
   Send(new InputMsg_MouseCaptureLost(routing_id_));
 }
 
 void RenderWidgetHostImpl::SetActive(bool active) {
   Send(new ViewMsg_SetActive(routing_id_, active));
 }
@@ skipping 1481 matching lines @@
 }
 #endif
 
 SkColorType RenderWidgetHostImpl::PreferredReadbackFormat() {
   if (view_)
     return view_->PreferredReadbackFormat();
   return kN32_SkColorType;
 }
 
 }  // namespace content