Fix a DCHECK fired when switching between screen capturing and windown capturing.

content/browser/media/capture/desktop_capture_device_aura.cc

 // Copyright 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/desktop_capture_device_aura.h"
 
 #include "base/logging.h"
 #include "base/metrics/histogram.h"
 #include "base/timer/timer.h"
 #include "cc/output/copy_output_request.h"
@@ skipping 297 matching lines @@
     scoped_refptr<media::VideoFrame> video_frame,
     base::TimeTicks start_time,
     const ThreadSafeCaptureOracle::CaptureFrameCallback& capture_frame_cb,
     scoped_ptr<cc::CopyOutputResult> result) {
   static bool first_call = true;
 
   bool succeeded = ProcessCopyOutputResponse(
       video_frame, start_time, capture_frame_cb, result.Pass());
 
   base::TimeDelta capture_time = base::TimeTicks::Now() - start_time;
-  UMA_HISTOGRAM_TIMES(
-      window_id_.type == DesktopMediaID::TYPE_SCREEN ? kUmaScreenCaptureTime
-                                                     : kUmaWindowCaptureTime,
-      capture_time);
+
+  // The two UMA_ blocks must be put in its own scope since it creates a static
+  // variable which expected constant histogram name.
+  if (window_id_.type == DesktopMediaID::TYPE_SCREEN) {
+    UMA_HISTOGRAM_TIMES(kUmaScreenCaptureTime, capture_time);
+  } else {
+    UMA_HISTOGRAM_TIMES(kUmaWindowCaptureTime, capture_time);
+  }
 
   if (first_call) {
     first_call = false;
     if (window_id_.type == DesktopMediaID::TYPE_SCREEN) {
       IncrementDesktopCaptureCounter(succeeded ? FIRST_SCREEN_CAPTURE_SUCCEEDED
                                                : FIRST_SCREEN_CAPTURE_FAILED);
     } else {
       IncrementDesktopCaptureCounter(succeeded
                                          ? FIRST_WINDOW_CAPTURE_SUCCEEDED
                                          : FIRST_WINDOW_CAPTURE_FAILED);
@@ skipping 197 matching lines @@
     scoped_ptr<Client> client) {
   DVLOG(1) << "Allocating " << params.requested_format.frame_size.ToString();
   core_->AllocateAndStart(params, client.Pass());
 }
 
 void DesktopCaptureDeviceAura::StopAndDeAllocate() {
   core_->StopAndDeAllocate();
 }
 
 }  // namespace content