Simplify computation of the invalidation rect for a frame.

third_party/WebKit/Source/web/WebPluginContainerImpl.cpp

Index: third_party/WebKit/Source/web/WebPluginContainerImpl.cpp
diff --git a/third_party/WebKit/Source/web/WebPluginContainerImpl.cpp b/third_party/WebKit/Source/web/WebPluginContainerImpl.cpp
index 7be53ac3319a576f79a2ce2916e262577e7501c0..be4e8497bd77a93e9e48251f826a5efbbbb7fa51 100644
--- a/third_party/WebKit/Source/web/WebPluginContainerImpl.cpp
+++ b/third_party/WebKit/Source/web/WebPluginContainerImpl.cpp
@@ -55,6 +55,7 @@
 #include "core/layout/HitTestResult.h"
 #include "core/layout/LayoutBox.h"
 #include "core/layout/LayoutPart.h"
+#include "core/layout/LayoutView.h"
 #include "core/loader/FrameLoadRequest.h"
 #include "core/page/FocusController.h"
 #include "core/page/Page.h"
@@ -944,6 +945,33 @@ void WebPluginContainerImpl::issuePaintInvalidations()
     m_pendingInvalidationRect = IntRect();
 }
 
+void WebPluginContainerImpl::computeClipRectsForPlugin(const HTMLFrameOwnerElement* ownerElement, IntRect& clippedAbsoluteRect, IntRect* unclippedIntAbsoluteRect) const
+{
+    ASSERT(ownerElement);
+
+    if (!ownerElement->layoutObject() || !ownerElement->layoutObject()->enclosingLayer()) {
+        clippedAbsoluteRect = IntRect();

[chrishtr, 2015/11/03 19:22:55]

I changed the code to just return an empty rect in scenarios where the plugin is
not attached to the layout tree properly. I think this will be fine.

[tommycli, 2015/11/03 20:10:22]

Acknowledged.

+        if (unclippedIntAbsoluteRect)
+            *unclippedIntAbsoluteRect = IntRect();
+
+        return;
+    }
+
+    LayoutView* rootView = m_element->document().view()->layoutView();
+    while (rootView->frame()->ownerLayoutObject())
+        rootView = rootView->frame()->ownerLayoutObject()->view();
+
+    const PaintLayer* enclosingLayer = ownerElement->layoutObject()->enclosingLayer();
+    LayoutRect unclippedAbsoluteRect = enclosingLayer->physicalBoundingBox(LayoutPoint());
+    enclosingLayer->layoutObject()->mapRectToPaintInvalidationBacking(rootView, unclippedAbsoluteRect, nullptr);

[chrishtr, 2015/11/03 19:22:55]

What this does: maps the box rect for the plugin container to the space of the
root view of the webpage, taking into account all transforms and clips along the
way. IOW it's the bounding box of the actual pixels the plugin can affect.

+
+    clippedAbsoluteRect = enclosingIntRect(unclippedAbsoluteRect);
+    clippedAbsoluteRect.intersect(rootView->frameView()->visibleContentRect());
+
+    if (unclippedIntAbsoluteRect)

[tommycli, 2015/11/03 20:10:22]

nit: Seems like you're doing the enclosingIntRect op twice. Can you just make a
copy from clippedAbsoluteRect to unclipped before you do the intersection?

[chrishtr, 2015/11/03 21:24:56]

Done.

+        *unclippedIntAbsoluteRect = enclosingIntRect(unclippedAbsoluteRect);
+}
+
 void WebPluginContainerImpl::calculateGeometry(IntRect& windowRect, IntRect& clipRect, IntRect& unobscuredRect, Vector<IntRect>& cutOutRects)
 {
     windowRect = toFrameView(parent())->contentsToRootFrame(frameRect());
@@ -958,10 +986,11 @@ void WebPluginContainerImpl::calculateGeometry(IntRect& windowRect, IntRect& cli
     if (m_element->layoutObject()->document().layoutView()) {
         // Take our element and get the clip rect from the enclosing layer and
         // frame view.
-        IntRect elementUnobscuredRect;
-        IntRect elementWindowClipRect = m_element->document().view()->clipRectsForFrameOwner(m_element, &elementUnobscuredRect);
-        clipRect.intersect(elementWindowClipRect);
-        unobscuredRect.intersect(elementUnobscuredRect);
+        IntRect unclippedAbsoluteRect;
+        IntRect clippedAbsoluteRect;
+        computeClipRectsForPlugin(m_element, clippedAbsoluteRect, &unclippedAbsoluteRect);
+        clipRect.intersect(clippedAbsoluteRect);
+        unobscuredRect.intersect(unclippedAbsoluteRect);
     }
 
     clipRect.move(-windowRect.x(), -windowRect.y());