cc: Abstract the LayerTreeHost.

cc/trees/layer_tree_host_interface.h

Index: cc/trees/layer_tree_host_interface.h
diff --git a/cc/trees/layer_tree_host_interface.h b/cc/trees/layer_tree_host_interface.h
new file mode 100644
index 0000000000000000000000000000000000000000..7308787b5ab10b1e31cc8ecbad4aba058a1c0c7f
--- /dev/null
+++ b/cc/trees/layer_tree_host_interface.h
@@ -0,0 +1,186 @@
+// Copyright 2016 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.
+
+#ifndef CC_TREES_LAYER_TREE_HOST_INTERFACE_H_
+#define CC_TREES_LAYER_TREE_HOST_INTERFACE_H_
+
+#include "base/macros.h"
+#include "cc/base/cc_export.h"
+#include "cc/debug/micro_benchmark.h"
+#include "cc/input/top_controls_state.h"
+
+namespace base {
+class TimeTicks;
+}  // namespace base
+
+namespace gfx {
+class Rect;
+}  // namespace gfx
+
+namespace cc {
+class InputHandler;
+class LayerTree;
+class LayerTreeDebugState;
+class LayerTreeMutator;
+class LayerTreeSettings;
+class OutputSurface;
+class SwapPromiseMonitor;
+class TaskRunnerProvider;
+
+// TODO(khushalsagar): Will be renamed to LayerTreeHost.
+class CC_EXPORT LayerTreeHostInterface {
+ public:
+  virtual ~LayerTreeHostInterface() {}
+
+  // Returns the process global unique identifier for this LayerTreeHost.
+  virtual int GetId() const = 0;
+
+  // The current source frame number. This is incremented for each main frame
+  // update(commit) pushed to the compositor thread.
+  virtual int SourceFrameNumber() const = 0;
+
+  // Returns the LayerTree that holds the main frame state pushed to the
+  // LayerTreeImpl on commit.
+  virtual LayerTree* GetLayerTree() = 0;
+  virtual const LayerTree* GetLayerTree() const = 0;
+
+  // Returns the TaskRunnerProvider used to access the main and compositor
+  // thread task runners.
+  virtual TaskRunnerProvider* GetTaskRunnerProvider() const = 0;
+
+  // Returns the settings used by this host.
+  virtual const LayerTreeSettings& GetSettings() const = 0;
+
+  // Sets the client id used to generate the SurfaceId that uniquely identifies
+  // the Surfaces produced by this compositor.
+  virtual void SetSurfaceClientId(uint32_t client_id) = 0;
+
+  // Sets the LayerTreeMutator interface used to directly mutate the compositor
+  // state on the compositor thread. (Compositor-Worker)
+  virtual void SetLayerTreeMutator(
+      std::unique_ptr<LayerTreeMutator> mutator) = 0;
+
+  // Call this function when you expect there to be a swap buffer.
+  // See swap_promise.h for how to use SwapPromise.
+  virtual void QueueSwapPromise(std::unique_ptr<SwapPromise> swap_promise) = 0;
+
+  // Sets whether the content is suitable to use Gpu Rasterization.
+  virtual void SetHasGpuRasterizationTrigger(bool has_trigger) = 0;
+
+  // Visibility and OutputSurface -------------------------------
+
+  virtual void SetVisible(bool visible) = 0;
+  virtual bool IsVisible() const = 0;
+
+  // Called in response to an OutputSurface request made to the client using
+  // LayerTreeHostClient::RequestNewOutputSurface. The client will be informed
+  // of the OutputSurface initialization status using DidInitializaOutputSurface
+  // or DidFailToInitializeOutputSurface. The request is completed when the host
+  // successfully initializes an OutputSurface.
+  virtual void SetOutputSurface(
+      std::unique_ptr<OutputSurface> output_surface) = 0;
+
+  // Forces the host to immediately release all references to the OutputSurface,
+  // if any. Can be safely called any time.
+  virtual std::unique_ptr<OutputSurface> ReleaseOutputSurface() = 0;
+
+  // Frame Scheduling (main and compositor frames) requests -------
+
+  // Requests a main frame update even if no content has changed. This is used,
+  // for instance in the case of RequestAnimationFrame from blink to ensure the
+  // main frame update is run on the next tick without pre-emptively forcing a
+  // full commit synchronization or layer updates.
+  virtual void SetNeedsAnimate() = 0;
+
+  // Requests a main frame update and also ensure that the host pulls layer
+  // updates from the client, even if no content might have changed, without
+  // forcing a full commit synchronization.
+  virtual void SetNeedsUpdateLayers() = 0;
+
+  // Requests that the next main frame update performs a full commit
+  // synchronization.
+  virtual void SetNeedsCommit() = 0;
+
+  // Returns true if a main frame (for any pipeline stage above) has been
+  // requested.
+  virtual bool BeginMainFrameRequested() const = 0;
+
+  // Returns true if a main frame with commit synchronization has been
+  // requested.
+  virtual bool CommitRequested() const = 0;
+
+  // Enables/disables the compositor from requesting main frame updates from the
+  // client.
+  virtual void SetDeferCommits(bool defer_commits) = 0;
+
+  // Synchronously performs a main frame update and layer updates. Used only in
+  // single threaded mode when the compositor's internal scheduling is disabled.
+  virtual void LayoutAndUpdateLayers() = 0;
+
+  // Synchronously performs a complete main frame update, commit and compositor
+  // frame. Used only in single threaded mode when the compositor's internal
+  // scheduling is disabled.
+  virtual void Composite(base::TimeTicks frame_begin_time) = 0;
+
+  // Requests a redraw (compositor frame) for the complete viewport.
+  virtual void SetNeedsRedraw() = 0;
+
+  // Requests a redraw (compositor frame) for the given rect.
+  virtual void SetNeedsRedrawRect(const gfx::Rect& damage_rect) = 0;
+
+  // Requests a main frame (including layer updates) and ensures that this main
+  // frame results in a redraw for the complete viewport when producing the
+  // CompositorFrame.
+  virtual void SetNextCommitForcesRedraw() = 0;
+
+  // Input Handling ---------------------------------------------
+
+  // Notifies the compositor that input from the browser is being throttled till
+  // the next commit. The compositor will prioritize activation of the pending
+  // tree so a commit can be performed.
+  virtual void NotifyInputThrottledUntilCommit() = 0;
+
+  // Sets the state of the top controls. (Used for URL bar animations on
+  // android).
+  virtual void UpdateTopControlsState(TopControlsState constraints,
+                                      TopControlsState current,
+                                      bool animate) = 0;
+
+  // Returns a reference to the InputHandler used to respond to input events on
+  // the compositor thread.
+  virtual const base::WeakPtr<InputHandler>& GetInputHandler() const = 0;
+
+  // Informs the compositor that an active fling gesture being processed on the
+  // main thread has been finished.
+  virtual void DidStopFlinging() = 0;
+
+  // Debugging and benchmarks ---------------------------------
+  virtual void SetDebugState(const LayerTreeDebugState& debug_state) = 0;
+  virtual const LayerTreeDebugState& GetDebugState() const = 0;
+
+  // Returns the id of the benchmark on success, 0 otherwise.
+  virtual int ScheduleMicroBenchmark(
+      const std::string& benchmark_name,
+      std::unique_ptr<base::Value> value,
+      const MicroBenchmark::DoneCallback& callback) = 0;
+
+  // Returns true if the message was successfully delivered and handled.
+  virtual bool SendMessageToMicroBenchmark(
+      int id,
+      std::unique_ptr<base::Value> value) = 0;
+
+  // Methods used internally in cc. These are not intended to be a part of the
+  // public API for use by the embedder ----------------------
+
+  // When a SwapPromiseMonitor is created on the main thread, it calls
+  // InsertSwapPromiseMonitor() to register itself with LayerTreeHost.
+  // When the monitor is destroyed, it calls RemoveSwapPromiseMonitor()
+  // to unregister itself.
+  virtual void InsertSwapPromiseMonitor(SwapPromiseMonitor* monitor) = 0;
+  virtual void RemoveSwapPromiseMonitor(SwapPromiseMonitor* monitor) = 0;
+};
+
+}  // namespace cc
+
+#endif  // CC_TREES_LAYER_TREE_HOST_INTERFACE_H_