Allocate textures based purely on viewport size

bug:5211417

Allocate textures based upon viewport size, instead of visible nr of tiles. This
will help prevent rare OOM issues triggering from a certain position in the
page.

Change-Id: Ib43fef0e0b9b8e4e26df448d67bb159a105e300c

1 files changed, 5 insertions, 2 deletions

diff --git a/Source/WebCore/platform/graphics/android/GLWebViewState.cpp b/Source/WebCore/platform/graphics/android/GLWebViewState.cpp
index d85d8b7..5764a6b 100644
--- a/Source/WebCore/platform/graphics/android/GLWebViewState.cpp
+++ b/Source/WebCore/platform/graphics/android/GLWebViewState.cpp
@@ -393,8 +393,11 @@ void GLWebViewState::setViewport(SkRect& viewport, float scale)
             static_cast<int>(ceilf(viewport.fRight * invTileContentWidth)),
             static_cast<int>(ceilf(viewport.fBottom * invTileContentHeight)));
 
-    int maxTextureCount = (m_viewportTileBounds.width() + TILE_PREFETCH_DISTANCE * 2) *
-            (m_viewportTileBounds.height() + TILE_PREFETCH_DISTANCE * 2) * 2;
+    // allocate max possible number of tiles visible with this viewport
+    int viewMaxTileX = static_cast<int>(ceilf((viewport.width()-1) * invTileContentWidth)) + 1;
+    int viewMaxTileY = static_cast<int>(ceilf((viewport.height()-1) * invTileContentHeight)) + 1;
+    int maxTextureCount = (viewMaxTileX + TILE_PREFETCH_DISTANCE * 2) *
+        (viewMaxTileY + TILE_PREFETCH_DISTANCE * 2) * 2;
     TilesManager::instance()->setMaxTextureCount(maxTextureCount);
     m_tiledPageA->updateBaseTileSize();
     m_tiledPageB->updateBaseTileSize();