Expose a way to set a view's base background color.

Source/web/WebViewImpl.cpp

Index: Source/web/WebViewImpl.cpp
diff --git a/Source/web/WebViewImpl.cpp b/Source/web/WebViewImpl.cpp
index dcad19b352389879f734234ca6fe73442cc48d20..f2e5168d9e3c472a85f197bc5b1f0d16ce6b0937 100644
--- a/Source/web/WebViewImpl.cpp
+++ b/Source/web/WebViewImpl.cpp
@@ -427,6 +427,7 @@ WebViewImpl::WebViewImpl(WebViewClient* client)
     , m_showDebugBorders(false)
     , m_continuousPaintingEnabled(false)
     , m_showScrollBottleneckRects(false)
+    , m_baseBackgroundColor(Color::white)
 {
     Page::PageClients pageClients;
     pageClients.chromeClient = &m_chromeClientImpl;
@@ -2461,11 +2462,11 @@ WebColor WebViewImpl::backgroundColor() const
     if (isTransparent())
         return Color::transparent;
     if (!m_page)
-        return Color::white;
+        return m_baseBackgroundColor;
     FrameView* view = m_page->mainFrame()->view();
     StyleColor backgroundColor = view->documentBackgroundColor();
     if (!backgroundColor.isValid())
-        return Color::white;
+        return m_baseBackgroundColor;
     return backgroundColor.rgb();
 }
 
@@ -3578,6 +3579,19 @@ bool WebViewImpl::isTransparent() const
     return m_isTransparent;
 }
 
+void WebViewImpl::setBaseBackgroundColor(WebColor color)
+{
+    if (m_baseBackgroundColor == color)
+        return;
+
+    m_baseBackgroundColor = color;
+
+    m_page->mainFrame()->view()->updateBackgroundRecursively(color, m_isTransparent);

[jamesr, 2013/07/25 00:02:28]

hmm, why recursive? won't this only change the background color on the root
frameview?

[jamesr, 2013/07/25 00:16:06]

I'm pretty sure calling FrameView::setBaseBackgroundColor() is the right thing
to do. it already has logic to call
renderView()->layer()->backing()->updateContentsOpaque(), so you don't have to
add that other call.

[joth, 2013/07/25 00:39:43]

Done.

(just to clarify: I am relying on the existing updateContentsOpaque() either way
: I haven't added any new call to it just rearranged it to use the already
null-checked 'backing' local)

+
+    if (m_layerTreeView)
+        m_layerTreeView->setBackgroundColor(backgroundColor());
+}
+
 void WebViewImpl::setIsActive(bool active)
 {
     if (page() && page()->focusController())