MediaStreamCaptureIndicator: fix crash due to destruction on wrong thread

BUG=141831

Review URL: https://chromiumcodereview.appspot.com/10825313

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@151565 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/media/media_stream_capture_indicator.cc

@@ -122,7 +122,6 @@ MediaStreamCaptureIndicator::MediaStreamCaptureIndicator()
       mic_image_(NULL),
       camera_image_(NULL),
       balloon_image_(NULL),
-      ALLOW_THIS_IN_INITIALIZER_LIST(tracker_(this)),
       request_index_(0) {
 }
 
@@ -274,7 +273,8 @@ void MediaStreamCaptureIndicator::ShowBalloon(
     pending_messages_[request_index_++] =
         l10n_util::GetStringFUTF16(message_id,
                                    UTF8ToUTF16(extension->name()));
-    tracker_.LoadImage(
+    EnsureImageLoadingTracker();
+    tracker_->LoadImage(
         extension,
         extension->GetIconResource(32, ExtensionIconSet::MATCH_BIGGER),
         gfx::Size(32, 32),
@@ -307,6 +307,10 @@ void MediaStreamCaptureIndicator::OnImageLoaded(
 void MediaStreamCaptureIndicator::Hide() {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
   DCHECK(tabs_.empty());
+
+  // We have to destroy |tracker_| on the UI thread.
+  tracker_.reset();
+
   if (!status_icon_)
     return;
 
@@ -445,3 +449,12 @@ void MediaStreamCaptureIndicator::RemoveCaptureDeviceTab(
   UpdateStatusTrayIconContextMenu();
 }
 
+void MediaStreamCaptureIndicator::EnsureImageLoadingTracker() {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  if (tracker_.get())
+    return;
+
+  tracker_.reset(new ImageLoadingTracker(this));
+  pending_messages_.clear();
+  request_index_ = 0;
+}

chrome/browser/media/media_stream_capture_indicator.h

@@ -9,6 +9,7 @@
 #include <vector>
 
 #include "base/memory/ref_counted.h"
+#include "base/memory/scoped_ptr.h"
 #include "chrome/browser/extensions/image_loading_tracker.h"
 #include "content/public/common/media_stream_request.h"
 #include "ui/base/models/simple_menu_model.h"
@@ -127,6 +128,9 @@ class MediaStreamCaptureIndicator
   // UpdateStatusTrayIconContextMenu().
   void UpdateStatusTrayIconDisplay(bool audio, bool video);
 
+  // Initializes image loading state.
+  void EnsureImageLoadingTracker();
+
   // Reference to our status icon - owned by the StatusTray. If null,
   // the platform doesn't support status icons.
   StatusIcon* status_icon_;
@@ -141,7 +145,7 @@ class MediaStreamCaptureIndicator
   CaptureDeviceTabs tabs_;
 
   // Tracks the load of extension icons.
-  ImageLoadingTracker tracker_;
+  scoped_ptr<ImageLoadingTracker> tracker_;
   // The messages to display when extension images are loaded. The index
   // corresponds to the index of the associated LoadImage request.
   std::map<int, string16> pending_messages_;