viz: Add method to disable auto throttling in FrameSinkVideoCapturer

As long as DevTools eyedropper tool is concerned, a snapshot is useless
if any sort of downscaling has happened on it. Add an option to disable
auto-throttling so that we get the highest resolution possible in any
circumstances. Also added a missing call to SetMinSizeChangePeriod.

Bug: 813929
Cq-Include-Trybots: master.tryserver.chromium.android:android_optional_gpu_tests_rel
Change-Id: I9cca167e6f015bd12d8ce64c9ba04d87847f1c44
Reviewed-on: https://chromium-review.googlesource.com/963309
Commit-Queue: Saman Sami <samans@chromium.org>
Reviewed-by: Yuri Wiitala <miu@chromium.org>
Reviewed-by: Tom Sepez <tsepez@chromium.org>
Reviewed-by: Andrey Kosyakov <caseq@chromium.org>
Cr-Commit-Position: refs/heads/master@{#543918}

chrome/browser/devtools/devtools_eye_dropper.cc

@@ -66,6 +66,8 @@ void DevToolsEyeDropper::AttachToHost(content::RenderWidgetHost* host) {
       gfx::Size(1, 1),
       gfx::Size(media::limits::kMaxDimension, media::limits::kMaxDimension),
       false);
+  video_capturer_->SetAutoThrottlingEnabled(false);
+  video_capturer_->SetMinSizeChangePeriod(base::TimeDelta());
   video_capturer_->SetMinCapturePeriod(base::TimeDelta::FromSeconds(1) /
                                        kMaxFrameRate);
 

components/viz/service/frame_sinks/video_capture/frame_sink_video_capturer_impl.cc

@@ -215,6 +215,10 @@ void FrameSinkVideoCapturerImpl::SetResolutionConstraints(
   RefreshEntireSourceSoon();
 }
 
+void FrameSinkVideoCapturerImpl::SetAutoThrottlingEnabled(bool enabled) {
+  oracle_.SetAutoThrottlingEnabled(enabled);
+}
+
 void FrameSinkVideoCapturerImpl::ChangeTarget(
     const FrameSinkId& frame_sink_id) {
   DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);

components/viz/service/frame_sinks/video_capture/frame_sink_video_capturer_impl.h

@@ -99,6 +99,7 @@ class VIZ_SERVICE_EXPORT FrameSinkVideoCapturerImpl final
   void SetResolutionConstraints(const gfx::Size& min_size,
                                 const gfx::Size& max_size,
                                 bool use_fixed_aspect_ratio) final;
+  void SetAutoThrottlingEnabled(bool enabled) final;
   void ChangeTarget(const FrameSinkId& frame_sink_id) final;
   void Start(mojom::FrameSinkVideoConsumerPtr consumer) final;
   void Stop() final;

content/browser/media/capture/frame_sink_video_capture_device_unittest.cc

@@ -91,6 +91,7 @@ class MockFrameSinkVideoCapturer : public viz::mojom::FrameSinkVideoCapturer {
                void(const gfx::Size& min_size,
                     const gfx::Size& max_size,
                     bool use_fixed_aspect_ratio));
+  MOCK_METHOD1(SetAutoThrottlingEnabled, void(bool));
   MOCK_METHOD1(ChangeTarget, void(const viz::FrameSinkId& frame_sink_id));
   void Start(viz::mojom::FrameSinkVideoConsumerPtr consumer) final {
     DCHECK_NOT_ON_DEVICE_THREAD();

media/capture/content/video_capture_oracle.cc

@@ -108,6 +108,20 @@ void VideoCaptureOracle::SetCaptureSizeConstraints(
                                      use_fixed_aspect_ratio);
 }
 
+void VideoCaptureOracle::SetAutoThrottlingEnabled(bool enabled) {
+  if (auto_throttling_enabled_ == enabled)
+    return;
+  auto_throttling_enabled_ = enabled;
+
+  // When not auto-throttling, have the CaptureResolutionChooser target the max
+  // resolution within constraints.
+  if (!enabled)
+    resolution_chooser_.SetTargetFrameArea(std::numeric_limits<int>::max());
+
+  if (next_frame_number_ > 0)
+    CommitCaptureSizeAndReset(GetFrameTimestamp(next_frame_number_ - 1));
+}
+
 void VideoCaptureOracle::SetSourceSize(const gfx::Size& source_size) {
   resolution_chooser_.SetSourceSize(source_size);
   // If the |resolution_chooser_| computed a new capture size, that will become

media/capture/content/video_capture_oracle.h

@@ -51,6 +51,10 @@ class CAPTURE_EXPORT VideoCaptureOracle {
                                  const gfx::Size& max_size,
                                  bool use_fixed_aspect_ratio);
 
+  // Specifies whether the oracle should automatically adjust the capture size
+  // in response to end-to-end utilization.
+  void SetAutoThrottlingEnabled(bool enabled);
+
   // Get/Update the source content size.  Changes may not have an immediate
   // effect on the proposed capture size, as the oracle will prevent too-
   // frequent changes from occurring.
@@ -181,7 +185,7 @@ class CAPTURE_EXPORT VideoCaptureOracle {
 
   // Set to false to prevent the oracle from automatically adjusting the capture
   // size in response to end-to-end utilization.
-  const bool auto_throttling_enabled_;
+  bool auto_throttling_enabled_;
 
   // The minimum amount of time that must pass between changes to the capture
   // size.

services/viz/privileged/interfaces/compositing/frame_sink_video_capture.mojom

@@ -88,7 +88,9 @@ interface FrameSinkVideoCapturer {
 
   // Specifies the minimum amount of time that must elapse between changing the
   // size of video frames. This can be set to zero to disable resize throttling,
-  // which means each video frame could have a different size.
+  // which means each video frame could have a different size. Note that
+  // setting this period too low can result in erratic frame sizing behaviour;
+  // consider disabling auto-throttling in such cases.
   //
   // Default, if never called: 3 seconds.
   SetMinSizeChangePeriod(mojo.common.mojom.TimeDelta min_period);
@@ -107,6 +109,15 @@ interface FrameSinkVideoCapturer {
   SetResolutionConstraints(gfx.mojom.Size min_size, gfx.mojom.Size max_size,
                            bool use_fixed_aspect_ratio);
 
+  // Specifies whether capture resolution should be automatically adjusted
+  // within the bounds provided to SetReslutionConstraints in response to
+  // utilization feedback from the consumer and the buffer pool. When set to
+  // false, the capturer will always use the highest resolution within
+  // constraints that doesn't exceed the source size.
+  //
+  // Default, if never called: true.
+  SetAutoThrottlingEnabled(bool enabled);
+
   // Targets a different compositor frame sink. This may be called anytime,
   // before or after Start().
   ChangeTarget(FrameSinkId frame_sink_id);