Implement all resolution change policies for desktop and tab capture.

content/browser/media/capture/web_contents_tracker.cc

 // Copyright (c) 2013 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/media/capture/web_contents_tracker.h"
 
 #include "base/thread_task_runner_handle.h"
 #include "content/browser/frame_host/render_frame_host_impl.h"
 #include "content/browser/renderer_host/render_widget_host_impl.h"
 #include "content/public/browser/browser_thread.h"
@@ skipping 26 matching lines @@
         BrowserThread::UI, FROM_HERE,
         base::Bind(&WebContentsTracker::StartObservingWebContents, this,
                    render_process_id, main_render_frame_id));
   }
 }
 
 void WebContentsTracker::Stop() {
   DCHECK(task_runner_->BelongsToCurrentThread());
 
   callback_.Reset();
+  resize_callback_.Reset();
 
   if (BrowserThread::CurrentlyOn(BrowserThread::UI)) {
     WebContentsObserver::Observe(NULL);
   } else {
     BrowserThread::PostTask(
         BrowserThread::UI, FROM_HERE,
         base::Bind(&WebContentsTracker::Observe, this,
                    static_cast<WebContents*>(NULL)));
   }
 }
@@ skipping 14 matching lines @@
   if (!rwh) {
     RenderFrameHostImpl* const rfh =
         static_cast<RenderFrameHostImpl*>(wc->GetMainFrame());
     if (rfh)
       rwh = rfh->GetRenderWidgetHost();
   }
 
   return rwh;
 }
 
+void WebContentsTracker::SetResizeChangeCallback(
+    const base::Closure& callback) {
+  DCHECK(!task_runner_.get() || task_runner_->BelongsToCurrentThread());
+  resize_callback_ = callback;
+}
+
 void WebContentsTracker::OnPossibleTargetChange(bool force_callback_run) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
 
   RenderWidgetHost* const rwh = GetTargetRenderWidgetHost();
   if (rwh == last_target_ && !force_callback_run)
     return;
   DVLOG(1) << "Will report target change from RenderWidgetHost@" << last_target_
            << " to RenderWidgetHost@" << rwh;
   last_target_ = rwh;
 
   if (task_runner_->BelongsToCurrentThread()) {
-    MaybeDoCallback(rwh);
-  } else {
-    task_runner_->PostTask(
-        FROM_HERE,
-        base::Bind(&WebContentsTracker::MaybeDoCallback, this, rwh));
+    MaybeDoCallback(!!rwh);

[Wez, 2015/05/15 21:36:06]

rwh != nullptr here and below; !!rwh looks weird!

[miu, 2015/05/15 21:41:03]

Done.

+    return;
   }
+
+  task_runner_->PostTask(
+      FROM_HERE,
+      base::Bind(&WebContentsTracker::MaybeDoCallback, this, !!rwh));
 }
 
-void WebContentsTracker::MaybeDoCallback(RenderWidgetHost* rwh) {
+void WebContentsTracker::MaybeDoCallback(bool was_still_tracking) {
   DCHECK(task_runner_->BelongsToCurrentThread());
 
   if (!callback_.is_null())
-    callback_.Run(rwh);
+    callback_.Run(was_still_tracking);
+  if (was_still_tracking)
+    MaybeDoResizeCallback();
+}
+
+void WebContentsTracker::MaybeDoResizeCallback() {
+  DCHECK(task_runner_->BelongsToCurrentThread());
+
+  if (!resize_callback_.is_null())
+    resize_callback_.Run();
 }
 
 void WebContentsTracker::StartObservingWebContents(int render_process_id,
                                                    int main_render_frame_id) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
 
   Observe(WebContents::FromRenderFrameHost(RenderFrameHost::FromID(
       render_process_id, main_render_frame_id)));
   DVLOG_IF(1, !web_contents())
       << "Could not find WebContents associated with main RenderFrameHost "
       << "referenced by render_process_id=" << render_process_id
       << ", routing_id=" << main_render_frame_id;
 
   OnPossibleTargetChange(true);
 }
 
 void WebContentsTracker::RenderFrameDeleted(
     RenderFrameHost* render_frame_host) {
   OnPossibleTargetChange(false);
 }
 
 void WebContentsTracker::RenderFrameHostChanged(RenderFrameHost* old_host,
                                                 RenderFrameHost* new_host) {
   OnPossibleTargetChange(false);
 }
 
+void WebContentsTracker::MainFrameWasResized(bool width_changed) {
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
+
+  if (task_runner_->BelongsToCurrentThread()) {
+    MaybeDoResizeCallback();
+    return;
+  }
+
+  task_runner_->PostTask(
+      FROM_HERE,
+      base::Bind(&WebContentsTracker::MaybeDoResizeCallback, this));
+}
+
 void WebContentsTracker::WebContentsDestroyed() {
   Observe(NULL);
   OnPossibleTargetChange(false);
 }
 
 void WebContentsTracker::DidShowFullscreenWidget(int routing_id) {
   OnPossibleTargetChange(false);
 }
 
 void WebContentsTracker::DidDestroyFullscreenWidget(int routing_id) {
   OnPossibleTargetChange(false);
 }
 
 }  // namespace content