Tab Audio Capture: Browser-side connect/disconnect functionality.

content/browser/renderer_host/media/web_contents_capture_util.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/media/web_contents_capture_util.h"
 
 #include "base/string_number_conversions.h"
 #include "base/string_piece.h"
+#include "content/public/browser/browser_thread.h"
+#include "content/public/browser/render_process_host.h"
+#include "content/public/browser/render_view_host.h"
+#include "content/public/browser/web_contents.h"
 
 namespace content {
 
+// static
 bool WebContentsCaptureUtil::ExtractTabCaptureTarget(
     const std::string& device_id,
     int* render_process_id,
     int* render_view_id) {
   const size_t sep_pos = device_id.find(':');
   if (sep_pos == std::string::npos)
     return false;
 
   const base::StringPiece component1(device_id.data(), sep_pos);
   const base::StringPiece component2(device_id.data() + sep_pos + 1,
                                      device_id.length() - sep_pos - 1);
 
   return (base::StringToInt(component1, render_process_id) &&
           base::StringToInt(component2, render_view_id));
 }
 
+WebContentsCaptureUtil::RenderViewTracker::RenderViewTracker() {}
+
+WebContentsCaptureUtil::RenderViewTracker::~RenderViewTracker() {
+  DCHECK(!web_contents()) << "BUG: Still observering!";
+}
+
+void WebContentsCaptureUtil::RenderViewTracker::Start(
+    int render_process_id, int render_view_id,
+    const ChangeCallback& callback) {
+  {

[Alpha Left Google, 2012/11/28 20:02:25]

I would like to keep things simple for this patch. This looks like is for the
video device. I think we should make that change later as there might be other
solution when we visit the problem.

+    base::AutoLock guard(lock_);
+    callback_ = callback;
+  }
+  BrowserThread::PostTask(
+      BrowserThread::UI, FROM_HERE,
+      base::Bind(&RenderViewTracker::LookUpAndObserveWebContents, this,
+                 render_process_id, render_view_id));
+}
+
+void WebContentsCaptureUtil::RenderViewTracker::Stop() {
+  {

[Alpha Left Google, 2012/11/28 20:02:25]

As suggested I think we don't need to use lock for this change, let's not worry
about video in this CL.

[miu, 2012/11/28 22:05:50]

Done.

+    base::AutoLock guard(lock_);
+    callback_.Reset();
+  }
+  BrowserThread::PostTask(
+      BrowserThread::UI, FROM_HERE,
+      base::Bind(&RenderViewTracker::Observe, this,
+                 static_cast<WebContents*>(NULL)));
+}
+
+void WebContentsCaptureUtil::RenderViewTracker::OnWebContentsChangeEvent() {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+
+  WebContents* const wc = web_contents();
+  RenderViewHost* const rvh = wc ? wc->GetRenderViewHost() : NULL;
+  RenderProcessHost* const rph = rvh ? rvh->GetProcess() : NULL;
+
+  const int render_process_id = rph ? rph->GetID() : MSG_ROUTING_NONE;
+  const int render_view_id = rvh ? rvh->GetRoutingID() : MSG_ROUTING_NONE;
+
+  base::AutoLock guard(lock_);
+  if (!callback_.is_null()) {
+    callback_.Run(render_process_id, render_view_id);
+  }
+}
+
+void WebContentsCaptureUtil::RenderViewTracker::LookUpAndObserveWebContents(
+    int render_process_id, int render_view_id) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+
+  RenderViewHost* const rvh =
+      RenderViewHost::FromID(render_process_id, render_view_id);
+  DVLOG_IF(1, !rvh) << "RenderViewHost::FromID("
+                    << render_process_id << ", " << render_view_id
+                    << ") returned NULL.";
+  Observe(rvh ? WebContents::FromRenderViewHost(rvh) : NULL);
+  DVLOG_IF(1, !web_contents())
+      << "WebContents::FromRenderViewHost(" << rvh << ") returned NULL.";
+
+  OnWebContentsChangeEvent();
+}
+
+void WebContentsCaptureUtil::RenderViewTracker::RenderViewReady() {
+  OnWebContentsChangeEvent();
+}
+
+void WebContentsCaptureUtil::RenderViewTracker::WebContentsDestroyed(
+    WebContents* web_contents) {
+  OnWebContentsChangeEvent();
+}
+
 }  // namespace content