WIP Handle AwContents needing multiple live functors.

android_webview/browser/browser_view_renderer.cc

 // Copyright 2014 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 "android_webview/browser/browser_view_renderer.h"
 
 #include <utility>
 
 #include "android_webview/browser/browser_view_renderer_client.h"
 #include "android_webview/browser/child_frame.h"
@@ skipping 74 matching lines @@
 BrowserViewRenderer* BrowserViewRenderer::FromWebContents(
     content::WebContents* web_contents) {
   return BrowserViewRendererUserData::GetBrowserViewRenderer(web_contents);
 }
 
 BrowserViewRenderer::BrowserViewRenderer(
     BrowserViewRendererClient* client,
     const scoped_refptr<base::SingleThreadTaskRunner>& ui_task_runner)
     : client_(client),
       ui_task_runner_(ui_task_runner),
-      compositor_frame_consumer_(nullptr),
+      current_compositor_frame_consumer_(nullptr),
       compositor_(NULL),
       is_paused_(false),
       view_visible_(false),
       window_visible_(false),
       attached_to_window_(false),
       hardware_enabled_(false),
       dip_scale_(0.f),
       page_scale_factor_(1.f),
       min_page_scale_factor_(0.f),
       max_page_scale_factor_(0.f),
       on_new_picture_enable_(false),
       clear_view_(false),
       offscreen_pre_raster_(false),
       next_compositor_id_(1) {}
 
 BrowserViewRenderer::~BrowserViewRenderer() {
   DCHECK(compositor_map_.empty());
-  SetCompositorFrameConsumer(nullptr);
-}
-
-void BrowserViewRenderer::SetCompositorFrameConsumer(
-    CompositorFrameConsumer* compositor_frame_consumer) {
-  if (compositor_frame_consumer == compositor_frame_consumer_) {
-    return;
-  }
-  if (compositor_frame_consumer_) {
-    compositor_frame_consumer_->DeleteHardwareRendererOnUI();
-    ReturnUnusedResource(
-        compositor_frame_consumer_->PassUncommittedFrameOnUI());
-    ReturnResourceFromParent(compositor_frame_consumer_);
-    compositor_frame_consumer_->SetCompositorFrameProducer(nullptr);
-  }
-  compositor_frame_consumer_ = compositor_frame_consumer;
-  if (compositor_frame_consumer_) {
-    compositor_frame_consumer_->SetCompositorFrameProducer(this);
+  while (compositor_frame_consumers_.size()) {
+    RemoveCompositorFrameConsumer(*compositor_frame_consumers_.begin());
   }
 }
 
+void BrowserViewRenderer::SetCurrentCompositorFrameConsumer(
+    CompositorFrameConsumer* compositor_frame_consumer) {
+  if (compositor_frame_consumer == current_compositor_frame_consumer_) {
+    return;
+  }
+  current_compositor_frame_consumer_ = compositor_frame_consumer;
+  if (current_compositor_frame_consumer_) {
+    compositor_frame_consumers_.insert(current_compositor_frame_consumer_);
+    if (current_compositor_frame_consumer_->GetCompositorFrameProducer() !=
+        this) {
+      if (current_compositor_frame_consumer_->GetCompositorFrameProducer()) {

[boliu, 2016/05/05 14:09:34]

this can't happen? we destroy the previous BVR before the new BVR is attached in
the pop up flow. just DCHECK somewhere that this can't happen

[Tobias Sargeant, 2016/05/05 19:06:46]

You're right. I've cleaned this up.

+        current_compositor_frame_consumer_->GetCompositorFrameProducer()
+            ->RemoveCompositorFrameConsumer(current_compositor_frame_consumer_);
+      }
+      current_compositor_frame_consumer_->SetCompositorFrameProducer(this);
+    }
+    OnParentDrawConstraintsUpdated(current_compositor_frame_consumer_);
+  }
+}
+
 void BrowserViewRenderer::RegisterWithWebContents(
     content::WebContents* web_contents) {
   web_contents->SetUserData(kBrowserViewRendererUserDataKey,
                             new BrowserViewRendererUserData(this));
 }
 
 void BrowserViewRenderer::TrimMemory() {
   DCHECK(ui_task_runner_->BelongsToCurrentThread());
   TRACE_EVENT0("android_webview", "BrowserViewRenderer::TrimMemory");
   // Just set the memory limit to 0 and drop all tiles. This will be reset to
@@ skipping 49 matching lines @@
   if (clear_view_) {
     TRACE_EVENT_INSTANT0("android_webview", "EarlyOut_ClearView",
                          TRACE_EVENT_SCOPE_THREAD);
     return false;
   }
 
   return true;
 }
 
 bool BrowserViewRenderer::OnDrawHardware() {
-  DCHECK(compositor_frame_consumer_);
+  DCHECK(current_compositor_frame_consumer_);
   TRACE_EVENT0("android_webview", "BrowserViewRenderer::OnDrawHardware");
 
-  compositor_frame_consumer_->InitializeHardwareDrawIfNeededOnUI();
+  current_compositor_frame_consumer_->InitializeHardwareDrawIfNeededOnUI();
 
   if (!CanOnDraw()) {
     return false;
   }
 
-  compositor_frame_consumer_->SetScrollOffsetOnUI(last_on_draw_scroll_offset_);
+  current_compositor_frame_consumer_->SetScrollOffsetOnUI(
+      last_on_draw_scroll_offset_);
   hardware_enabled_ = true;
 
   external_draw_constraints_ =
-      compositor_frame_consumer_->GetParentDrawConstraintsOnUI();
+      current_compositor_frame_consumer_->GetParentDrawConstraintsOnUI();
 
-  ReturnResourceFromParent(compositor_frame_consumer_);
+  ReturnResourceFromParent(current_compositor_frame_consumer_);
   UpdateMemoryPolicy();
 
   gfx::Size surface_size(size_);
   gfx::Rect viewport(surface_size);
   gfx::Rect clip = viewport;
   gfx::Transform transform_for_tile_priority =
       external_draw_constraints_.transform;
 
   // If the WebView is on a layer, WebView does not know what transform is
   // applied onto the layer so global visible rect does not make sense here.
   // In this case, just use the surface rect for tiling.
   gfx::Rect viewport_rect_for_tile_priority;
 
   // Leave viewport_rect_for_tile_priority empty if offscreen_pre_raster_ is on.
   if (!offscreen_pre_raster_ && !external_draw_constraints_.is_layer) {
     viewport_rect_for_tile_priority = last_on_draw_global_visible_rect_;
   }
 
   content::SynchronousCompositor::Frame frame =
       compositor_->DemandDrawHw(surface_size,
                                 gfx::Transform(),
                                 viewport,
                                 clip,
                                 viewport_rect_for_tile_priority,
                                 transform_for_tile_priority);
   if (!frame.frame.get()) {
     TRACE_EVENT_INSTANT0("android_webview", "NoNewFrame",
                          TRACE_EVENT_SCOPE_THREAD);
-    hardware_enabled_ = compositor_frame_consumer_->HasFrameOnUI();
+    hardware_enabled_ = current_compositor_frame_consumer_->HasFrameOnUI();
     if (!hardware_enabled_)
       UpdateMemoryPolicy();
     return hardware_enabled_;
   }
 
   std::unique_ptr<ChildFrame> child_frame = base::WrapUnique(new ChildFrame(
       frame.output_surface_id, std::move(frame.frame),
       GetCompositorID(compositor_), viewport_rect_for_tile_priority.IsEmpty(),
       transform_for_tile_priority, offscreen_pre_raster_,
       external_draw_constraints_.is_layer));
 
-  ReturnUnusedResource(compositor_frame_consumer_->PassUncommittedFrameOnUI());
-  compositor_frame_consumer_->SetFrameOnUI(std::move(child_frame));
+  ReturnUnusedResource(
+      current_compositor_frame_consumer_->PassUncommittedFrameOnUI());
+  current_compositor_frame_consumer_->SetFrameOnUI(std::move(child_frame));
   return true;
 }
 
-void BrowserViewRenderer::OnParentDrawConstraintsUpdated() {
-  DCHECK(compositor_frame_consumer_);
-  PostInvalidate();
-  external_draw_constraints_ =
-      compositor_frame_consumer_->GetParentDrawConstraintsOnUI();
-  UpdateMemoryPolicy();
+void BrowserViewRenderer::OnParentDrawConstraintsUpdated(
+    CompositorFrameConsumer* compositor_frame_consumer) {
+  DCHECK(compositor_frame_consumer);

[boliu, 2016/05/05 14:09:34]

DCHECK compositor frame is in set

[Tobias Sargeant, 2016/05/05 19:06:45]

Don't need to, because being equal to the current consumer implies that.

[boliu, 2016/05/06 15:53:13]

Well, you are DCHECK-ing that guarantee.

+  if (compositor_frame_consumer == current_compositor_frame_consumer_) {

[boliu, 2016/05/05 14:09:34]

nit: we usually prefer

if (foo)
  return;

since that avoids indenting the whole method

[Tobias Sargeant, 2016/05/05 19:06:46]

Done.

+    PostInvalidate();
+    external_draw_constraints_ =
+        current_compositor_frame_consumer_->GetParentDrawConstraintsOnUI();
+    UpdateMemoryPolicy();
+  }
 }
 
-void BrowserViewRenderer::OnCompositorFrameConsumerWillDestroy() {
-  DCHECK(compositor_frame_consumer_);
-  SetCompositorFrameConsumer(nullptr);
+void BrowserViewRenderer::RemoveCompositorFrameConsumer(
+    CompositorFrameConsumer* compositor_frame_consumer) {
+  DCHECK(compositor_frame_consumers_.count(compositor_frame_consumer));
+  compositor_frame_consumers_.erase(compositor_frame_consumer);
+  if (current_compositor_frame_consumer_ == compositor_frame_consumer) {
+    SetCurrentCompositorFrameConsumer(nullptr);
+  }
+
+  // At this point the compositor frame consumer has to hand back all resources
+  // to the child compositor.
+  compositor_frame_consumer->DeleteHardwareRendererOnUI();
+  ReturnUnusedResource(compositor_frame_consumer->PassUncommittedFrameOnUI());
+  ReturnResourceFromParent(compositor_frame_consumer);
+  compositor_frame_consumer->SetCompositorFrameProducer(nullptr);
 }
 
 void BrowserViewRenderer::ReturnUnusedResource(
     std::unique_ptr<ChildFrame> child_frame) {
   if (!child_frame.get() || !child_frame->frame.get())
     return;
 
   cc::CompositorFrameAck frame_ack;
   cc::TransferableResource::ReturnResources(
       child_frame->frame->delegated_frame_data->resource_list,
@@ skipping 146 matching lines @@
 }
 
 void BrowserViewRenderer::OnComputeScroll(base::TimeTicks animation_time) {
   if (!compositor_)
     return;
   TRACE_EVENT0("android_webview", "BrowserViewRenderer::OnComputeScroll");
   compositor_->OnComputeScroll(animation_time);
 }
 
 void BrowserViewRenderer::ReleaseHardware() {
-  if (compositor_frame_consumer_) {
+  for (auto compositor_frame_consumer_ : compositor_frame_consumers_) {
     ReturnUnusedResource(
         compositor_frame_consumer_->PassUncommittedFrameOnUI());
     ReturnResourceFromParent(compositor_frame_consumer_);
     DCHECK(compositor_frame_consumer_->ReturnedResourcesEmptyOnUI());
   }
   hardware_enabled_ = false;
   UpdateMemoryPolicy();
 }
 
 bool BrowserViewRenderer::IsVisible() const {
@@ skipping 268 matching lines @@
   base::StringAppendF(&str,
                       "overscroll_rounding_error_: %s ",
                       overscroll_rounding_error_.ToString().c_str());
   base::StringAppendF(
       &str, "on_new_picture_enable: %d ", on_new_picture_enable_);
   base::StringAppendF(&str, "clear_view: %d ", clear_view_);
   return str;
 }
 
 }  // namespace android_webview