"Buttery Smooth" Tab Capture.

content/browser/renderer_host/media/video_capture_controller.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/video_capture_controller.h"
 
 #include <map>
 #include <set>
 
 #include "base/bind.h"
@@ skipping 23 matching lines @@
 
 namespace {
 
 static const int kInfiniteRatio = 99999;
 
 #define UMA_HISTOGRAM_ASPECT_RATIO(name, width, height) \
     UMA_HISTOGRAM_SPARSE_SLOWLY( \
         name, \
         (height) ? ((width) * 100) / (height) : kInfiniteRatio);
 
-// The number of buffers that VideoCaptureBufferPool should allocate.
-const int kNoOfBuffers = 3;
-
 class PoolBuffer : public media::VideoCaptureDevice::Client::Buffer {
  public:
   PoolBuffer(const scoped_refptr<VideoCaptureBufferPool>& pool,
              int buffer_id,
              void* data,
              size_t size)
       : Buffer(buffer_id, data, size), pool_(pool) {
     DCHECK(pool_);
   }
 
@@ skipping 121 matching lines @@
 
   // The controller to which we post events.
   const base::WeakPtr<VideoCaptureController> controller_;
 
   // The pool of shared-memory buffers used for capturing.
   const scoped_refptr<VideoCaptureBufferPool> buffer_pool_;
 
   bool first_frame_;
 };
 
-VideoCaptureController::VideoCaptureController()
-    : buffer_pool_(new VideoCaptureBufferPool(kNoOfBuffers)),
+VideoCaptureController::VideoCaptureController(int max_buffers)
+    : buffer_pool_(new VideoCaptureBufferPool(max_buffers)),
       state_(VIDEO_CAPTURE_STATE_STARTED),
       weak_ptr_factory_(this) {
 }
 
 VideoCaptureController::VideoCaptureDeviceClient::VideoCaptureDeviceClient(
     const base::WeakPtr<VideoCaptureController>& controller,
     const scoped_refptr<VideoCaptureBufferPool>& buffer_pool)
     : controller_(controller), buffer_pool_(buffer_pool), first_frame_(true) {}
 
 VideoCaptureController::VideoCaptureDeviceClient::~VideoCaptureDeviceClient() {}
@@ skipping 479 matching lines @@
   }
   return NULL;
 }
 
 int VideoCaptureController::GetClientCount() {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
   return controller_clients_.size();
 }
 
 }  // namespace content