Implement transform/clip support for Android WebView.

cc/output/direct_renderer.cc

Index: cc/output/direct_renderer.cc
diff --git a/cc/output/direct_renderer.cc b/cc/output/direct_renderer.cc
index e2c17b8a7cdb320d480f5b4905c49bc848a8982b..52498aedcd8f1e8fd8d427e1e2bdfeee9427b150 100644
--- a/cc/output/direct_renderer.cc
+++ b/cc/output/direct_renderer.cc
@@ -82,6 +82,7 @@ void DirectRenderer::QuadRectTransform(gfx::Transform* quad_rect_transform,
 // static
 void DirectRenderer::InitializeMatrices(DrawingFrame* frame,
                                         gfx::Rect draw_rect,
+                                        gfx::Rect window_rect,
                                         bool flip_y) {
   if (flip_y) {
     frame->projection_matrix = OrthoProjectionMatrix(draw_rect.x(),
@@ -94,19 +95,26 @@ void DirectRenderer::InitializeMatrices(DrawingFrame* frame,
                                                      draw_rect.y(),
                                                      draw_rect.bottom());
   }
-  frame->window_matrix =
-      window_matrix(0, 0, draw_rect.width(), draw_rect.height());
+
+  frame->window_matrix = window_matrix(window_rect.x(),
+                                       window_rect.y(),
+                                       window_rect.width(),
+                                       window_rect.height());
   frame->flipped_y = flip_y;
 }
 
-// static
 gfx::Rect DirectRenderer::MoveScissorToWindowSpace(
     const DrawingFrame* frame, const gfx::RectF& scissor_rect) {
   gfx::Rect scissor_rect_in_canvas_space = gfx::ToEnclosingRect(scissor_rect);
-  // The scissor coordinates must be supplied in viewport space so we need to
+  // The scissor coordinates must be supplied in window space so we need to
   // offset by the relative position of the top left corner of the current
   // render pass.
   gfx::Rect framebuffer_output_rect = frame->current_render_pass->output_rect;
+  if (!frame->current_texture) {
+    framebuffer_output_rect = gfx::Rect(output_surface_->SurfaceSize());
+    scissor_rect_in_canvas_space.Offset(client_->DeviceViewport().x(),
+                                        client_->DeviceViewport().y());
+  }
   scissor_rect_in_canvas_space.set_x(
       scissor_rect_in_canvas_space.x() - framebuffer_output_rect.x());
   if (frame->flipped_y && !frame->current_texture) {
@@ -121,8 +129,10 @@ gfx::Rect DirectRenderer::MoveScissorToWindowSpace(
 }
 
 DirectRenderer::DirectRenderer(RendererClient* client,
+                               OutputSurface* output_surface,
                                ResourceProvider* resource_provider)
     : Renderer(client),
+      output_surface_(output_surface),
       resource_provider_(resource_provider) {}
 
 DirectRenderer::~DirectRenderer() {}
@@ -197,7 +207,13 @@ void DirectRenderer::DrawFrame(RenderPassList* render_passes_in_draw_order) {
   frame.root_damage_rect =
       Capabilities().using_partial_swap && client_->AllowPartialSwap() ?
       root_render_pass->damage_rect : root_render_pass->output_rect;
-  frame.root_damage_rect.Intersect(gfx::Rect(ViewportSize()));
+  frame.root_damage_rect.Intersect(gfx::Rect(client_->DeviceViewport().size()));
+
+  // Only reshape when we know we are going to draw. Otherwise, the reshape
+  // can leave the window at the wrong size if we never draw and the proper
+  // viewport size is never set.
+  output_surface_->Reshape(client_->DeviceViewport().size(),
+                           client_->DeviceScaleFactor());
 
   BeginDrawingFrame(&frame);
   for (size_t i = 0; i < render_passes_in_draw_order->size(); ++i) {
@@ -327,8 +343,16 @@ bool DirectRenderer::UseRenderPass(DrawingFrame* frame,
 
   if (render_pass == frame->root_render_pass) {
     BindFramebufferToOutputSurface(frame);
-    InitializeMatrices(frame, render_pass->output_rect, FlippedFramebuffer());
-    SetDrawViewportSize(render_pass->output_rect.size());
+    gfx::Rect viewport = client_->DeviceViewport();
+    if (FlippedFramebuffer())
+      viewport.set_y(output_surface_->SurfaceSize().height() -
+                     viewport.bottom());
+    InitializeMatrices(
+        frame,
+        render_pass->output_rect,
+        viewport,
+        FlippedFramebuffer());
+    SetDrawViewport(viewport);
     return true;
   }