Fix screen capture slowness in Chrome OS feedback report.

content/browser/renderer_host/media/video_capture_device_impl.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/renderer_host/media/video_capture_device_impl.h"
 
 #include "base/basictypes.h"
 #include "base/bind.h"
 #include "base/callback_forward.h"
 #include "base/callback_helpers.h"
@@ skipping 26 matching lines @@
     capture_machine->Stop();
     capture_machine.reset();
   }
 }
 
 }  // namespace
 
 ThreadSafeCaptureOracle::ThreadSafeCaptureOracle(
     scoped_ptr<media::VideoCaptureDevice::Client> client,
     scoped_ptr<VideoCaptureOracle> oracle,
-    const gfx::Size& capture_size,
+    const gfx::Size& max_frame_size,
     int frame_rate)
     : client_(client.Pass()),
       oracle_(oracle.Pass()),
-      capture_size_(capture_size),
-      frame_rate_(frame_rate) {}
+      max_frame_size_(max_frame_size),
+      frame_rate_(frame_rate) {
+  // Set initial capture size to maximum frame size.
+  capture_size_ = max_frame_size_;
+}
 
 ThreadSafeCaptureOracle::~ThreadSafeCaptureOracle() {}
 
 bool ThreadSafeCaptureOracle::ObserveEventAndDecideCapture(
     VideoCaptureOracle::Event event,
     base::Time event_time,
     scoped_refptr<media::VideoFrame>* storage,
     CaptureFrameCallback* callback) {
   base::AutoLock guard(lock_);
 
@@ skipping 52 matching lines @@
       gfx::Rect(capture_size_),
       capture_size_,
       static_cast<uint8*>(output_buffer->data()),
       output_buffer->size(),
       base::SharedMemory::NULLHandle(),
       base::TimeDelta(),
       base::Closure());
   return true;
 }
 
+void ThreadSafeCaptureOracle::UpdateCaptureSize(const gfx::Size& source_size) {
+  base::AutoLock guard(lock_);
+
+  // The capture resolution should not exceed the source frame size.
+  // In other words it should downscale the image but not upscale it.
+  gfx::Size capture_size = max_frame_size_;
+  capture_size.SetToMin(source_size);
+  capture_size_ = capture_size;
+}
+
 void ThreadSafeCaptureOracle::Stop() {
   base::AutoLock guard(lock_);
   client_.reset();
 }
 
 void ThreadSafeCaptureOracle::ReportError() {
   base::AutoLock guard(lock_);
   if (client_)
     client_->OnError();
 }
@@ skipping 136 matching lines @@
     return;
 
   if (oracle_proxy_)
     oracle_proxy_->ReportError();
 
   StopAndDeAllocate();
   TransitionStateTo(kError);
 }
 
 }  // namespace content