[BlackBerry] Rotate device from landscape to portrait during youtube streaming will cause device screen flash with video list page
https://bugs.webkit.org/show_bug.cgi?id=120364

Patch by Jacky Jiang <zhajiang@blackberry.com> on 2013-08-27
Reviewed by Rob Buis.
Internally reviewed by Arvid Nilsson.

Source/WebCore:

JIRA 461232
When rotating device from landscape mode to portrait mode, we updated
texture contents based on landscape mode front visibility and back
visibility on WebKit thread at the very beginning and the landscape mode
tiles wouldn't be able to cover the portrait mode screen which resulted
in the screen flash.
It's hard to compute front visibility information on WebKit thread because
it doesn't know where the layers will be on the screen. Therefore, the
front visibility won't be updated until the first time we draw textures
on compositing thread.
The patch traverses through LayerWebKitThread and LayerCompositingThread
and discards back visibility and front visibility respectively if there
is a pending orientation. In this way, we can pick up layerTilerPrefillRect
as visibleRect instead of the visibleRect from the stale visibilities
and add more tiles for uncovered screen when updating texture contents
on WebKit thread.
The patch also fixes a bug that we prune tiles based on the stale
m_requiredTextureSize in pruneTextures(). We should prune tiles based
on the updated pendingTextureSize instead.

* platform/graphics/blackberry/LayerCompositingThread.cpp:
(WebCore::LayerCompositingThread::discardFrontVisibility):
* platform/graphics/blackberry/LayerCompositingThread.h:
* platform/graphics/blackberry/LayerCompositingThreadClient.h:
(WebCore::LayerCompositingThreadClient::discardFrontVisibility):
* platform/graphics/blackberry/LayerRenderer.cpp:
(WebCore::LayerRenderer::discardFrontVisibility):
* platform/graphics/blackberry/LayerRenderer.h:
* platform/graphics/blackberry/LayerTiler.cpp:
(WebCore::LayerTiler::discardFrontVisibility):
(WebCore::LayerTiler::processTextureJob):
(WebCore::LayerTiler::pruneTextures):
(WebCore::LayerTiler::discardBackVisibility):
* platform/graphics/blackberry/LayerTiler.h:
* platform/graphics/blackberry/LayerWebKitThread.cpp:
(WebCore::LayerWebKitThread::discardBackVisibility):
* platform/graphics/blackberry/LayerWebKitThread.h:

Source/WebKit/blackberry:

* Api/WebPage.cpp:
(BlackBerry::WebKit::WebPagePrivate::setViewportSize):
(BlackBerry::WebKit::WebPagePrivate::discardLayerVisibilities):
(BlackBerry::WebKit::WebPagePrivate::discardFrontVisibilityCompositingThread):
* Api/WebPageCompositor.cpp:
(BlackBerry::WebKit::WebPageCompositorPrivate::discardFrontVisibility):
* Api/WebPageCompositor_p.h:
* Api/WebPage_p.h:
* WebKitSupport/FrameLayers.cpp:
(BlackBerry::WebKit::FrameLayers::discardBackVisibility):
* WebKitSupport/FrameLayers.h:

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@154701 268f45cc-cd09-0410-ab3c-d52691b4dbfc