cc: Partial tile update for one-copy raster.

cc/resources/one_copy_tile_task_worker_pool.cc

Index: cc/resources/one_copy_tile_task_worker_pool.cc
diff --git a/cc/resources/one_copy_tile_task_worker_pool.cc b/cc/resources/one_copy_tile_task_worker_pool.cc
index 23f372c15e2b13add87aacaa046b6a62528ac335..3754ccd11a8d226dbb00354d4ac8c37aab621d57 100644
--- a/cc/resources/one_copy_tile_task_worker_pool.cc
+++ b/cc/resources/one_copy_tile_task_worker_pool.cc
@@ -26,31 +26,48 @@ class RasterBufferImpl : public RasterBuffer {
                    ResourceProvider* resource_provider,
                    ResourcePool* resource_pool,
                    ResourceFormat resource_format,
-                   const Resource* resource)
+                   const TileTaskData& data)
       : worker_pool_(worker_pool),
         resource_provider_(resource_provider),
         resource_pool_(resource_pool),
-        resource_(resource),
-        raster_resource_(
-            resource_pool->AcquireResource(resource->size(), resource_format)),
+        tile_task_data_(data),
+        raster_resource_(resource_pool->AcquireResource(data.resource->size(),
+                                                        resource_format)),
+        previous_frame_raster_resource_(
+            resource_pool->TryAcquireOldResource(data.resource->size(),
+                                                 resource_format,
+                                                 data.previous_tile_id)),
         lock_(new ResourceProvider::ScopedWriteLockGpuMemoryBuffer(
             resource_provider_,
             raster_resource_->id())),
-        sequence_(0) {}
+        sequence_(0) {
+    if (previous_frame_raster_resource_) {
+      previous_frame_lock_.reset(
+          new ResourceProvider::ScopedReadLockGpuMemoryBuffer(
+              resource_provider_, previous_frame_raster_resource_->id()));
+    }
+  }
 
   ~RasterBufferImpl() override {
-    // Release write lock in case a copy was never scheduled.
+    // Release write/read lock in case a copy was never scheduled.
     lock_.reset();
+    previous_frame_lock_.reset();
 
     // Make sure any scheduled copy operations are issued before we release the
     // raster resource.
     if (sequence_)
       worker_pool_->AdvanceLastIssuedCopyTo(sequence_);
 
-    // Return raster resource to pool so it can be used by another RasterBuffer
+    // Return resources to pool so they can be used by another RasterBuffer
     // instance.
-    if (raster_resource_)
-      resource_pool_->ReleaseResource(raster_resource_.Pass());
+    if (raster_resource_) {
+      resource_pool_->ReleaseResource(raster_resource_.Pass(),
+                                      tile_task_data_.new_tile_id);
+    }
+    if (previous_frame_raster_resource_) {
+      resource_pool_->ReleaseResource(raster_resource_.Pass(),
+                                      tile_task_data_.previous_tile_id);
+    }
   }
 
   // Overridden from RasterBuffer:
@@ -58,17 +75,21 @@ class RasterBufferImpl : public RasterBuffer {
                 const gfx::Rect& rect,
                 float scale) override {
     sequence_ = worker_pool_->PlaybackAndScheduleCopyOnWorkerThread(
-        lock_.Pass(), raster_resource_.Pass(), resource_, raster_source, rect,
-        scale);
+        lock_.Pass(), raster_resource_.Pass(), previous_frame_lock_.Pass(),
+        previous_frame_raster_resource_.Pass(), tile_task_data_, raster_source,
+        rect, scale);
   }
 
  private:
   OneCopyTileTaskWorkerPool* worker_pool_;
   ResourceProvider* resource_provider_;
   ResourcePool* resource_pool_;
-  const Resource* resource_;
+  TileTaskData tile_task_data_;
   scoped_ptr<ScopedResource> raster_resource_;
+  scoped_ptr<ScopedResource> previous_frame_raster_resource_;
   scoped_ptr<ResourceProvider::ScopedWriteLockGpuMemoryBuffer> lock_;
+  scoped_ptr<ResourceProvider::ScopedReadLockGpuMemoryBuffer>
+      previous_frame_lock_;
   CopySequenceNumber sequence_;
 
   DISALLOW_COPY_AND_ASSIGN(RasterBufferImpl);
@@ -92,8 +113,15 @@ const int kFailedAttemptsBeforeWaitIfNeeded = 256;
 OneCopyTileTaskWorkerPool::CopyOperation::CopyOperation(
     scoped_ptr<ResourceProvider::ScopedWriteLockGpuMemoryBuffer> write_lock,
     scoped_ptr<ScopedResource> src,
-    const Resource* dst)
-    : write_lock(write_lock.Pass()), src(src.Pass()), dst(dst) {
+    scoped_ptr<ResourceProvider::ScopedReadLockGpuMemoryBuffer>
+        previous_frame_read_lock,
+    scoped_ptr<ScopedResource> previous_frame_src,
+    const TileTaskData& data)
+    : write_lock(write_lock.Pass()),
+      src(src.Pass()),
+      previous_frame_read_lock(previous_frame_read_lock.Pass()),
+      previous_frame_src(previous_frame_src.Pass()),
+      tile_task_data(data) {
 }
 
 OneCopyTileTaskWorkerPool::CopyOperation::~CopyOperation() {
@@ -262,12 +290,11 @@ ResourceFormat OneCopyTileTaskWorkerPool::GetResourceFormat() {
 }
 
 scoped_ptr<RasterBuffer> OneCopyTileTaskWorkerPool::AcquireBufferForRaster(
-    const Resource* resource) {
-  DCHECK_EQ(resource->format(), resource_provider_->best_texture_format());
+    const TileTaskData& data) {
+  DCHECK_EQ(data.resource->format(), resource_provider_->best_texture_format());
   return make_scoped_ptr<RasterBuffer>(
       new RasterBufferImpl(this, resource_provider_, resource_pool_,
-                           resource_provider_->best_texture_format(),
-                           resource));
+                           resource_provider_->best_texture_format(), data));
 }
 
 void OneCopyTileTaskWorkerPool::ReleaseBufferForRaster(
@@ -279,7 +306,10 @@ CopySequenceNumber
 OneCopyTileTaskWorkerPool::PlaybackAndScheduleCopyOnWorkerThread(
     scoped_ptr<ResourceProvider::ScopedWriteLockGpuMemoryBuffer> write_lock,
     scoped_ptr<ScopedResource> src,
-    const Resource* dst,
+    scoped_ptr<ResourceProvider::ScopedReadLockGpuMemoryBuffer>
+        previous_frame_read_lock,
+    scoped_ptr<ScopedResource> previous_frame_src,
+    const TileTaskData& tile_task_data,
     const RasterSource* raster_source,
     const gfx::Rect& rect,
     float scale) {
@@ -326,14 +356,46 @@ OneCopyTileTaskWorkerPool::PlaybackAndScheduleCopyOnWorkerThread(
       DCHECK(rv);
       int stride;
       gpu_memory_buffer->GetStride(&stride);
+
+      // Copy from the previous_frame_src to src to reuse raster work if
+      // possible.
+      bool copied_from_previous = false;
+      if (previous_frame_src) {
+        gfx::GpuMemoryBuffer* previous_gpu_memory_buffer =
+            previous_frame_read_lock->GetGpuMemoryBuffer();
+        if (previous_gpu_memory_buffer) {
+          void* previous_data = NULL;
+          bool prv = previous_gpu_memory_buffer->Map(&previous_data);
+          DCHECK(prv);
+          int previous_stride;
+          previous_gpu_memory_buffer->GetStride(&previous_stride);
+
+          if (previous_stride == stride) {
+            size_t bytes = static_cast<size_t>(stride) * src->size().height();
+            memcpy(data, previous_data, bytes);
+            copied_from_previous = true;
+          }
+          previous_gpu_memory_buffer->Unmap();
+        }
+      }
+
+      gfx::Rect playback_rect = rect;
+      if (copied_from_previous) {
+        LOG(ERROR) << tile_task_data.raster_dirty_rect.ToString();
+        playback_rect.Intersect(tile_task_data.raster_dirty_rect);
+      }
+      DCHECK(!playback_rect.IsEmpty())
+          << "Why are we rastering a tile that's not dirty?";
       TileTaskWorkerPool::PlaybackToMemory(data, src->format(), src->size(),
-                                           stride, raster_source, rect, scale);
+                                           stride, raster_source, rect,
+                                           playback_rect, scale);
       gpu_memory_buffer->Unmap();
     }
   }
 
-  pending_copy_operations_.push_back(
-      make_scoped_ptr(new CopyOperation(write_lock.Pass(), src.Pass(), dst)));
+  pending_copy_operations_.push_back(make_scoped_ptr(new CopyOperation(
+      write_lock.Pass(), src.Pass(), previous_frame_read_lock.Pass(),
+      previous_frame_src.Pass(), tile_task_data)));
 
   // Acquire a sequence number for this copy operation.
   CopySequenceNumber sequence = next_copy_operation_sequence_++;
@@ -415,12 +477,19 @@ void OneCopyTileTaskWorkerPool::IssueCopyOperations(int64 count) {
     copy_operation->write_lock.reset();
 
     // Copy contents of source resource to destination resource.
-    resource_provider_->CopyResource(copy_operation->src->id(),
-                                     copy_operation->dst->id());
+    resource_provider_->CopyResource(
+        copy_operation->src->id(),
+        copy_operation->tile_task_data.resource->id());
 
     // Return source resource to pool where it can be reused once copy
     // operation has completed and resource is no longer busy.
-    resource_pool_->ReleaseResource(copy_operation->src.Pass());
+    resource_pool_->ReleaseResource(copy_operation->src.Pass(),
+                                    copy_operation->tile_task_data.new_tile_id);
+    if (copy_operation->previous_frame_src) {
+      resource_pool_->ReleaseResource(
+          copy_operation->previous_frame_src.Pass(),
+          copy_operation->tile_task_data.previous_tile_id);
+    }
   }
 }