Insert pinch zoom virtual viewport layers to graphics layer tree.

Source/WebKit/chromium/src/WebViewImpl.cpp

Index: Source/WebKit/chromium/src/WebViewImpl.cpp
diff --git a/Source/WebKit/chromium/src/WebViewImpl.cpp b/Source/WebKit/chromium/src/WebViewImpl.cpp
index 8792a6f93b56771340581b347dc000a3592e0af4..184e5a85cc022795ab0ceee41fa0840a52c28437 100644
--- a/Source/WebKit/chromium/src/WebViewImpl.cpp
+++ b/Source/WebKit/chromium/src/WebViewImpl.cpp
@@ -57,6 +57,7 @@
 #include "HTMLNames.h"
 #include "LinkHighlight.h"
 #include "PageWidgetDelegate.h"
+#include "PinchViewports.h"
 #include "PopupContainer.h"
 #include "PrerendererClientImpl.h"
 #include "SpeechInputClientImpl.h"
@@ -148,7 +149,6 @@
 #include "core/platform/graphics/chromium/LayerPainterChromium.h"
 #include "core/platform/graphics/gpu/SharedGraphicsContext3D.h"
 #include "core/platform/network/ResourceHandle.h"
-#include "core/rendering/RenderLayerCompositor.h"
 #include "core/rendering/RenderView.h"
 #include "core/rendering/RenderWidget.h"
 #include "core/rendering/TextAutosizer.h"
@@ -1611,8 +1611,11 @@ void WebViewImpl::resize(const WebSize& newSize)
         agentPrivate->webViewResized(newSize);
     if (!agentPrivate || !agentPrivate->metricsOverridden()) {
         WebFrameImpl* webFrame = mainFrameImpl();
-        if (webFrame->frameView())
+        if (webFrame->frameView()) {
             webFrame->frameView()->resize(m_size);
+            if (m_pinchViewports)
+                m_pinchViewports->setViewportSize(FloatSize(m_size.width, m_size.height));
+        }
     }
 
     if (settings()->viewportEnabled()) {
@@ -3806,11 +3809,28 @@ void WebViewImpl::setRootGraphicsLayer(GraphicsLayer* layer)
 {
     suppressInvalidations(true);
 
-    m_rootGraphicsLayer = layer;
-    m_rootLayer = layer ? layer->platformLayer() : 0;
+    if (page()->settings()->pinchVirtualViewportEnabled() && !m_pinchViewports)
+        m_pinchViewports = PinchViewports::create(this);

[jamesr, 2013/06/14 20:55:46]

do you need to tear the pinch viewports down when leaving compositing mode?

[wjmaclean, 2013/06/17 17:45:27]

I don't *think* so, though I could be convinced otherwise. Here's my reasoning:

1) I assume "leaving compositing mode" corresponds to (layer == 0) in
WebViewImpl::setRootGraphicsLayer(). In this case, any existing viewport layers
are disconnected from the tree, and so do nothing.

2) When the root graphics layer changes (and typically the RenderLayerCompositor
behind it), we disconnect and then re-connect the viewport layers. Since they
don't rely on anything outside PinchViewports (e.g. they don't rely on RLC to be
a client), this re-use should be OK.

In practice building the viewport layer structure once and re-using it seems to
have worked fine, and I am unaware if any reason why it shouldn't be ok. But,
I'm also OK with tearing it down and rebuilding each time if that seems safer.

+
+    if (m_pinchViewports) {
+        m_pinchViewports->setOverflowControlsHostLayer(layer);
+        if (layer) {
+            m_rootGraphicsLayer = m_pinchViewports->rootGraphicsLayer();
+            m_rootLayer = m_pinchViewports->rootGraphicsLayer()->platformLayer();
+        } else {
+            m_rootGraphicsLayer = 0;
+            m_rootLayer = 0;
+        }
+    } else {
+        m_rootGraphicsLayer = layer;
+        m_rootLayer = layer ? layer->platformLayer() : 0;
+    }
+
 
     setIsAcceleratedCompositingActive(layer);
 
+    // FIXME: We also need to tell the layer tree about the pinchViewport layers
+    // in a follow-on CL.
     if (m_layerTreeView) {
         if (m_rootLayer)
             m_layerTreeView->setRootLayer(*m_rootLayer);
@@ -3845,6 +3865,16 @@ WebCore::GraphicsLayerFactory* WebViewImpl::graphicsLayerFactory() const
     return m_graphicsLayerFactory.get();
 }
 
+WebCore::RenderLayerCompositor* WebViewImpl::compositor() const
+{
+    if (!page()
+        || !page()->mainFrame()
+        || !page()->mainFrame()->document()
+        || !page()->mainFrame()->document()->renderView())
+        return 0;
+    return page()->mainFrame()->document()->renderView()->compositor();
+}
+
 void WebViewImpl::registerForAnimations(WebLayer* layer)
 {
     if (m_layerTreeView)