Backout of bug 1208636 due to it causing large black areas on long pages (bug 1210411). rs=kats

gfx/layers/apz/src/APZCTreeManager.cpp

@@ -6,13 +6,11 @@
 #include "APZCTreeManager.h"
 #include "AsyncPanZoomController.h"
 #include "Compositor.h"                 // for Compositor
-#include "gfxPrefs.h"                   // for gfxPrefs
 #include "HitTestingTreeNode.h"         // for HitTestingTreeNode
 #include "InputBlockState.h"            // for InputBlockState
 #include "InputData.h"                  // for InputData, etc
 #include "Layers.h"                     // for Layer, etc
 #include "mozilla/dom/Touch.h"          // for Touch
-#include "mozilla/gfx/Logging.h"        // for gfx::TreeLog
 #include "mozilla/gfx/Point.h"          // for Point
 #include "mozilla/layers/APZThreadUtils.h"  // for AssertOnCompositorThread, etc
 #include "mozilla/layers/AsyncCompositionManager.h" // for ViewTransform
@@ -26,12 +24,14 @@
 #include "nsDebug.h"                    // for NS_WARNING
 #include "nsPoint.h"                    // for nsIntPoint
 #include "nsThreadUtils.h"              // for NS_IsMainThread
+#include "mozilla/gfx/Logging.h"        // for gfx::TreeLog
+#include "UnitTransforms.h"             // for ViewAs
+#include "gfxPrefs.h"                   // for gfxPrefs
 #include "OverscrollHandoffState.h"     // for OverscrollHandoffState
 #include "TaskThrottler.h"              // for TaskThrottler
 #include "TreeTraversal.h"              // for generic tree traveral algorithms
 #include "LayersLogging.h"              // for Stringify
 #include "Units.h"                      // for ParentlayerPixel
-#include "UnitTransforms.h"             // for ViewAs
 
 #define ENABLE_APZCTM_LOGGING 0
 // #define ENABLE_APZCTM_LOGGING 1

gfx/layers/apz/src/AsyncPanZoomController.cpp

@@ -63,7 +63,6 @@
 #include "nsStyleStruct.h"              // for nsTimingFunction
 #include "nsTArray.h"                   // for nsTArray, nsTArray_Impl, etc
 #include "nsThreadUtils.h"              // for NS_IsMainThread
-#include "prsystem.h"                   // for PR_GetPhysicalMemorySize
 #include "SharedMemoryBasic.h"          // for SharedMemoryBasic
 #include "WheelScrollAnimation.h"
 
@@ -330,11 +329,6 @@ using mozilla::gfx::PointTyped;
  * The multiplier we apply to the displayport size if it is not skating (see
  * documentation for the skate size multipliers above).
  *
- * \li\b apz.x_skate_highmem_adjust
- * \li\b apz.y_skate_highmem_adjust
- * On high memory systems, we adjust the displayport during skating
- * to be larger so we can reduce checkerboarding.
- *
  * \li\b apz.zoom_animation_duration_ms
  * This controls how long the zoom-to-rect animation takes.\n
  * Units: ms
@@ -350,16 +344,6 @@ StaticAutoPtr<ComputedTimingFunction> gZoomAnimationFunction;
  */
 StaticAutoPtr<ComputedTimingFunction> gVelocityCurveFunction;
 
-/**
- * Returns true if this is a high memory system and we can use
- * extra memory for a larger displayport to reduce checkerboarding.
- */
-static bool gIsHighMemSystem = false;
-static bool IsHighMemSystem()
-{
-  return gIsHighMemSystem;
-}
-
 /**
  * Maximum zoom amount, always used, even if a page asks for higher.
  */
@@ -818,10 +802,6 @@ AsyncPanZoomController::InitializeGlobalState()
                      gfxPrefs::APZCurveFunctionX2(),
                      gfxPrefs::APZCurveFunctionY2()));
   ClearOnShutdown(&gVelocityCurveFunction);
-
-  uint64_t sysmem = PR_GetPhysicalMemorySize();
-  uint64_t threshold = 1LL << 32; // 4 GB in bytes
-  gIsHighMemSystem = sysmem >= threshold;
 }
 
 AsyncPanZoomController::AsyncPanZoomController(uint64_t aLayersId,
@@ -2448,11 +2428,6 @@ CalculateDisplayPortSize(const CSSSize& aCompositionSize,
                         ? gfxPrefs::APZYStationarySizeMultiplier()
                         : gfxPrefs::APZYSkateSizeMultiplier();
 
-  if (IsHighMemSystem()) {
-    xMultiplier += gfxPrefs::APZXSkateHighMemAdjust();
-    yMultiplier += gfxPrefs::APZYSkateHighMemAdjust();
-  }
-
   // Ensure that it is at least as large as the visible area inflated by the
   // danger zone. If this is not the case then the "AboutToCheckerboard"
   // function in TiledContentClient.cpp will return true even in the stable

gfx/thebes/gfxPrefs.h

@@ -185,10 +185,8 @@ private:
   DECL_GFX_PREF(Live, "apz.velocity_bias",                     APZVelocityBias, float, 1.0f);
   DECL_GFX_PREF(Live, "apz.velocity_relevance_time_ms",        APZVelocityRelevanceTime, uint32_t, 150);
   DECL_GFX_PREF(Live, "apz.x_skate_size_multiplier",           APZXSkateSizeMultiplier, float, 1.5f);
-  DECL_GFX_PREF(Live, "apz.x_skate_highmem_adjust",            APZXSkateHighMemAdjust, float, 0.0f);
   DECL_GFX_PREF(Live, "apz.x_stationary_size_multiplier",      APZXStationarySizeMultiplier, float, 3.0f);
   DECL_GFX_PREF(Live, "apz.y_skate_size_multiplier",           APZYSkateSizeMultiplier, float, 2.5f);
-  DECL_GFX_PREF(Live, "apz.y_skate_highmem_adjust",            APZYSkateHighMemAdjust, float, 0.0f);
   DECL_GFX_PREF(Live, "apz.y_stationary_size_multiplier",      APZYStationarySizeMultiplier, float, 3.5f);
   DECL_GFX_PREF(Live, "apz.zoom_animation_duration_ms",        APZZoomAnimationDuration, int32_t, 250);
 

modules/libpref/init/all.js

@@ -588,8 +588,6 @@ pref("apz.smooth_scroll_repaint_interval", 16);
 pref("apz.pan_repaint_interval", 16);
 pref("apz.x_skate_size_multiplier", "2.5");
 pref("apz.y_skate_size_multiplier", "3.5");
-pref("apz.x_skate_highmem_adjust", "1.0");
-pref("apz.y_skate_highmem_adjust", "2.5");
 #else
 // Mobile prefs
 pref("apz.fling_repaint_interval", 75);
@@ -597,8 +595,6 @@ pref("apz.smooth_scroll_repaint_interval", 75);
 pref("apz.pan_repaint_interval", 250);
 pref("apz.x_skate_size_multiplier", "1.5");
 pref("apz.y_skate_size_multiplier", "2.5");
-pref("apz.x_skate_highmem_adjust", "0.0");
-pref("apz.y_skate_highmem_adjust", "0.0");
 #endif
 
 // APZ testing (bug 961289)