Android Webview IPC-based sync compositing

content/common/android/sync_compositor_messages.h

+// Copyright 2015 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 "cc/output/begin_frame_args.h"
+#include "cc/output/compositor_frame.h"
+#include "cc/output/compositor_frame_ack.h"
+#include "content/common/content_export.h"
+#include "content/common/content_param_traits.h"
+#include "content/common/input/input_event_ack_state.h"
+#include "ipc/ipc_message_macros.h"
+#include "third_party/WebKit/public/web/WebInputEvent.h"
+#include "ui/gfx/geometry/scroll_offset.h"
+
+#ifndef CONTENT_COMMON_ANDROID_SYNC_COMPOSITOR_MESSAGES_H_
+#define CONTENT_COMMON_ANDROID_SYNC_COMPOSITOR_MESSAGES_H_
+
+namespace content {
+
+struct SyncCompositorCommonBrowserParams {
+  SyncCompositorCommonBrowserParams();
+  SyncCompositorCommonBrowserParams(
+      size_t bytes_limit,
+      const gfx::ScrollOffset& root_scroll_offset);
+  ~SyncCompositorCommonBrowserParams();
+
+  size_t bytes_limit;
+  cc::CompositorFrameAck ack;
+  gfx::ScrollOffset root_scroll_offset;
+};
+
+struct SyncCompositorDemandDrawHwParams {
+  SyncCompositorDemandDrawHwParams();
+  SyncCompositorDemandDrawHwParams(
+      const gfx::Size& surface_size,
+      const gfx::Transform& transform,
+      const gfx::Rect& viewport,
+      const gfx::Rect& clip,
+      const gfx::Rect& viewport_rect_for_tile_priority,
+      const gfx::Transform& transform_for_tile_priority);
+  ~SyncCompositorDemandDrawHwParams();
+
+  gfx::Size surface_size;
+  gfx::Transform transform;
+  gfx::Rect viewport;
+  gfx::Rect clip;
+  gfx::Rect viewport_rect_for_tile_priority;
+  gfx::Transform transform_for_tile_priority;
+};
+
+struct SyncCompositorCommonRendererParams {
+  SyncCompositorCommonRendererParams();
+  SyncCompositorCommonRendererParams(
+      unsigned int version,
+      const gfx::ScrollOffset& total_scroll_offset,
+      const gfx::ScrollOffset& max_scroll_offset,
+      const gfx::SizeF& scrollable_size,
+      float page_scale_factor,
+      float min_page_scale_factor,
+      float max_page_scale_factor,
+      bool need_animate_scroll,
+      bool need_invalidate,
+      bool need_begin_frame,
+      bool did_activate_pending_tree);

[dcheng, 2015/11/04 09:47:41]

I'll leave it to your judgement, but one nice thing about not having a
constructor like this is that it's very clear that you're not accidentally
mixing up parameters.

Because there are so many parameters, and so many have the same type, it'd be
easy to accidentally typo the order, and the compiler would never notice.

[boliu, 2015/11/04 16:52:04]

Done.

So the upside of having the constructor means everything will be intialized to a
valid value (most of the default values aren't valid).

But then either way, it's a good thing there is only a single function that sets
all of these variables, so it really doesn't matter.

(I was going to make point about how these variables are not set twice in the
name of efficency, but then SynchronousCompositorProxy::ConstructCommonParams
doesn't construct this struct, so it's copied either way)

So, taking your suggestion. Removed this constructor and set the values
individually instead to make it more readable.

Also removed the constructor with parameters from BrowserParams. That's not used
anymore.

+  ~SyncCompositorCommonRendererParams();
+
+  unsigned int version;

[dcheng, 2015/11/04 09:47:41]

Explicitly size to uint32_t
(https://www.chromium.org/Home/chromium-security/education/security-tips-for-i...)

[boliu, 2015/11/04 16:52:04]

Done.

+  gfx::ScrollOffset total_scroll_offset;
+  gfx::ScrollOffset max_scroll_offset;
+  gfx::SizeF scrollable_size;
+  float page_scale_factor;
+  float min_page_scale_factor;
+  float max_page_scale_factor;
+  bool need_animate_scroll;
+  bool need_invalidate;
+  bool need_begin_frame;
+  bool did_activate_pending_tree;
+};
+
+}  // namespace content
+
+#endif  // CONTENT_COMMON_ANDROID_SYNC_COMPOSITOR_MESSAGES_H_
+
+// Multiply-included message file, hence no include guard.
+
+#undef IPC_MESSAGE_EXPORT
+#define IPC_MESSAGE_EXPORT CONTENT_EXPORT
+#define IPC_MESSAGE_START SyncCompositorMsgStart
+
+IPC_STRUCT_TRAITS_BEGIN(content::SyncCompositorCommonBrowserParams)
+  IPC_STRUCT_TRAITS_MEMBER(bytes_limit)
+  IPC_STRUCT_TRAITS_MEMBER(ack)
+  IPC_STRUCT_TRAITS_MEMBER(root_scroll_offset)
+IPC_STRUCT_TRAITS_END()
+
+IPC_STRUCT_TRAITS_BEGIN(content::SyncCompositorDemandDrawHwParams)
+  IPC_STRUCT_TRAITS_MEMBER(surface_size)
+  IPC_STRUCT_TRAITS_MEMBER(transform)
+  IPC_STRUCT_TRAITS_MEMBER(viewport)
+  IPC_STRUCT_TRAITS_MEMBER(clip)
+  IPC_STRUCT_TRAITS_MEMBER(viewport_rect_for_tile_priority)
+  IPC_STRUCT_TRAITS_MEMBER(transform_for_tile_priority)
+IPC_STRUCT_TRAITS_END()
+
+IPC_STRUCT_TRAITS_BEGIN(content::SyncCompositorCommonRendererParams)
+  IPC_STRUCT_TRAITS_MEMBER(version)
+  IPC_STRUCT_TRAITS_MEMBER(total_scroll_offset)
+  IPC_STRUCT_TRAITS_MEMBER(max_scroll_offset)
+  IPC_STRUCT_TRAITS_MEMBER(scrollable_size)
+  IPC_STRUCT_TRAITS_MEMBER(page_scale_factor)
+  IPC_STRUCT_TRAITS_MEMBER(min_page_scale_factor)
+  IPC_STRUCT_TRAITS_MEMBER(max_page_scale_factor)
+  IPC_STRUCT_TRAITS_MEMBER(need_animate_scroll)
+  IPC_STRUCT_TRAITS_MEMBER(need_invalidate)
+  IPC_STRUCT_TRAITS_MEMBER(need_begin_frame)
+  IPC_STRUCT_TRAITS_MEMBER(did_activate_pending_tree)
+IPC_STRUCT_TRAITS_END()
+
+IPC_SYNC_MESSAGE_ROUTED2_2(SyncCompositorMsg_HandleInputEvent,
+                           content::SyncCompositorCommonBrowserParams,
+                           IPC::WebInputEventPointer,
+                           content::SyncCompositorCommonRendererParams,
+                           content::InputEventAckState);
+
+IPC_SYNC_MESSAGE_ROUTED2_1(SyncCompositorMsg_BeginFrame,
+                           content::SyncCompositorCommonBrowserParams,
+                           cc::BeginFrameArgs,
+                           content::SyncCompositorCommonRendererParams);
+
+IPC_SYNC_MESSAGE_ROUTED2_1(SyncCompositorMsg_ComputeScroll,
+                           content::SyncCompositorCommonBrowserParams,
+                           base::TimeTicks,
+                           content::SyncCompositorCommonRendererParams);
+
+IPC_SYNC_MESSAGE_ROUTED2_2(SyncCompositorMsg_DemandDrawHw,
+                           content::SyncCompositorCommonBrowserParams,
+                           content::SyncCompositorDemandDrawHwParams,
+                           content::SyncCompositorCommonRendererParams,
+                           cc::CompositorFrame);
+
+IPC_MESSAGE_ROUTED1(SyncCompositorHostMsg_UpdateState,
+                    content::SyncCompositorCommonRendererParams);