base: Fix parsing and add dalvik-heap-limit

content/common/gpu/gpu_memory_manager.cc

Index: content/common/gpu/gpu_memory_manager.cc
diff --git a/content/common/gpu/gpu_memory_manager.cc b/content/common/gpu/gpu_memory_manager.cc
index 07a4d10782dc6521cfd449c9d0a82156ec00c0b6..89078e9b4fcea480a4c3ea98486b22c6b661bc5a 100644
--- a/content/common/gpu/gpu_memory_manager.cc
+++ b/content/common/gpu/gpu_memory_manager.cc
@@ -151,23 +151,44 @@ uint64 GpuMemoryManager::GetMaximumClientAllocation() const {
 #endif
 }
 
-uint64 GpuMemoryManager::CalcAvailableFromViewportArea(int viewport_area) {
-  // We can't query available GPU memory from the system on Android, but
-  // 18X the viewport and 50% of the dalvik heap size give us a good
-  // estimate of available GPU memory on a wide range of devices.
-  const int kViewportMultiplier = 18;
-  const unsigned int kComponentsPerPixel = 4; // GraphicsContext3D::RGBA
-  const unsigned int kBytesPerComponent = 1; // sizeof(GC3Dubyte)
-  uint64 viewport_limit = viewport_area * kViewportMultiplier *
-                                          kComponentsPerPixel *
-                                          kBytesPerComponent;
+uint64 GpuMemoryManager::CalcAvailableFromDalvikHeap() {
 #if !defined(OS_ANDROID)
-  return viewport_limit;
+  CHECK(false);
+  return 0;
 #else
+  // We can't query available GPU memory from the system on Android,
+  // but the dalvik heap size give us a good estimate of available
+  // GPU memory on a wide range of devices.
+
+  // The heap size tends to be about 1/4 of total ram on higher end
+  // devices, so we use 1/2 of that by default. For example both the
+  // Nexus 4/10 have 2GB of ram and 512MB Dalvik heap size. For lower
+  // end devices, 1/2 of the heap size can be too high, but this
+  // correlates well with having a small heap-growth-limit. So for
+  // devices with less ram, we factor in the growth limit.
+
+  // This is the result of the calculation below:
+  // Droid DNA 1080P  128MB
+  // Nexus S           56MB
+  // Galaxy Nexus     112MB
+  // Nexus 4/10       256MB
+  // Xoom              88MB
+
   static uint64 dalvik_limit = 0;
-  if (!dalvik_limit)
-      dalvik_limit = (base::SysInfo::DalvikHeapSizeMB() / 2) * 1024 * 1024;
-  return std::min(viewport_limit, dalvik_limit);
+  if (!dalvik_limit) {
+    uint64 heap_size   = base::SysInfo::DalvikHeapSizeMB();
+    uint64 heap_growth = base::SysInfo::DalvikHeapGrowthLimitMB();
+    uint64 limit = 0;
+
+    if (heap_size >= 350)
+        limit = heap_size / 2;
+    else
+        limit = (heap_size + (heap_growth * 2)) / 4;
+
+    dalvik_limit = limit * 1024 * 1024;
+  }
+
+  return dalvik_limit;
 #endif
 }
 
@@ -219,7 +240,7 @@ void GpuMemoryManager::UpdateAvailableGpuMemory() {
   }
 
 #if defined(OS_ANDROID)
-  bytes_available_gpu_memory_ = CalcAvailableFromViewportArea(max_surface_area);
+  bytes_available_gpu_memory_ = CalcAvailableFromDalvikHeap();
 #else
   if (!bytes_min)
     return;