Add dedicated windowToViewport method

third_party/WebKit/Source/web/ChromeClientImpl.cpp

Index: third_party/WebKit/Source/web/ChromeClientImpl.cpp
diff --git a/third_party/WebKit/Source/web/ChromeClientImpl.cpp b/third_party/WebKit/Source/web/ChromeClientImpl.cpp
index e728623d5c978578683a6067ec101d77ecff7e96..abd6d27d618af17f98af1063f4d90741030be7da 100644
--- a/third_party/WebKit/Source/web/ChromeClientImpl.cpp
+++ b/third_party/WebKit/Source/web/ChromeClientImpl.cpp
@@ -64,6 +64,7 @@
 #include "platform/weborigin/SecurityOrigin.h"
 #include "public/platform/Platform.h"
 #include "public/platform/WebCursorInfo.h"
+#include "public/platform/WebFloatRect.h"
 #include "public/platform/WebFrameScheduler.h"
 #include "public/platform/WebRect.h"
 #include "public/platform/WebURLRequest.h"
@@ -519,6 +520,14 @@ IntRect ChromeClientImpl::viewportToScreen(const IntRect& rectInViewport) const
     return screenRect;
 }
 
+FloatRect ChromeClientImpl::windowToViewport(const FloatRect& rectInWindow) const
+{
+    WebFloatRect viewportRect(rectInWindow);
+    if (m_webView->client())
+        m_webView->client()->convertWindowToViewport(&viewportRect);
+    return viewportRect;
+}
+
 WebScreenInfo ChromeClientImpl::screenInfo() const
 {
     return m_webView->client() ? m_webView->client()->screenInfo() : WebScreenInfo();