[Android WebView] First cut memory management

Based on simple algorithm of visible rect x constant.
Completely disregards the preferred allocation from based on
content of the page.

Constants extermined experimentally using current android
nexus devices.

BUG=286026

Review URL: https://chromiumcodereview.appspot.com/23572023

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@222372 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 57 insertions, 0 deletions

diff --git a/android_webview/browser/in_process_view_renderer.cc b/android_webview/browser/in_process_view_renderer.cc
index aebf732..07b4d67 100644
--- a/android_webview/browser/in_process_view_renderer.cc
+++ b/android_webview/browser/in_process_view_renderer.cc
@@ -17,10 +17,12 @@
 #include "base/debug/trace_event.h"
 #include "base/lazy_instance.h"
 #include "base/logging.h"
+#include "base/strings/string_number_conversions.h"
 #include "base/strings/stringprintf.h"
 #include "content/public/browser/android/synchronous_compositor.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/web_contents.h"
+#include "content/public/common/content_switches.h"
 #include "gpu/command_buffer/service/in_process_command_buffer.h"
 #include "third_party/skia/include/core/SkBitmap.h"
 #include "third_party/skia/include/core/SkBitmapDevice.h"
@@ -28,6 +30,7 @@
 #include "third_party/skia/include/core/SkGraphics.h"
 #include "third_party/skia/include/core/SkPicture.h"
 #include "third_party/skia/include/utils/SkCanvasStateUtils.h"
+#include "ui/gfx/android/device_display_info.h"
 #include "ui/gfx/skia_util.h"
 #include "ui/gfx/transform.h"
 #include "ui/gfx/vector2d_conversions.h"
@@ -143,6 +146,13 @@ AwDrawSWFunctionTable* g_sw_draw_functions = NULL;
 
 const int64 kFallbackTickTimeoutInMilliseconds = 20;
 
+
+// Used to calculate memory and resource allocation. Determined experimentally.
+size_t g_memory_multiplier = 15;
+const size_t kMaxNumTilesToFillDisplay = 20;
+const size_t kBytesPerPixel = 4;
+const size_t kMemoryAllocationStep = 10 * 1024 * 1024;
+
 class ScopedAllowGL {
  public:
   ScopedAllowGL();
@@ -276,6 +286,39 @@ void InProcessViewRenderer::WebContentsGone() {
   compositor_ = NULL;
 }
 
+// static
+void InProcessViewRenderer::CalculateTileMemoryPolicy() {
+  CommandLine* cl = CommandLine::ForCurrentProcess();
+  if (cl->HasSwitch(switches::kTileMemoryMultiplier)) {
+    std::string string_value =
+        cl->GetSwitchValueASCII(switches::kTileMemoryMultiplier);
+    int int_value;
+    if (base::StringToInt(string_value, &int_value) &&
+        int_value >= 2 && int_value <= 50) {
+      g_memory_multiplier = int_value;
+    }
+  }
+
+  if (cl->HasSwitch(switches::kDefaultTileWidth) ||
+      cl->HasSwitch(switches::kDefaultTileHeight)) {
+    return;
+  }
+
+  // TODO(boliu): Should use view context to get the display dimensions, and
+  // pass tile size in a per WebContents setting instead of through command
+  // line switch.
+  gfx::DeviceDisplayInfo info;
+  int default_tile_size = 256;
+
+  if (info.GetDisplayWidth() >= 1080)
+    default_tile_size = 512;
+
+  std::stringstream size;
+  size << default_tile_size;
+  cl->AppendSwitchASCII(switches::kDefaultTileWidth, size.str());
+  cl->AppendSwitchASCII(switches::kDefaultTileHeight, size.str());
+}
+
 bool InProcessViewRenderer::RequestProcessGL() {
   return client_->RequestDrawGL(NULL);
 }
@@ -372,6 +415,18 @@ void InProcessViewRenderer::DrawGL(AwDrawGLInfo* draw_info) {
     return;
   }
 
+  // Update memory budget. This will no-op in compositor if the policy has not
+  // changed since last draw.
+  content::SynchronousCompositorMemoryPolicy policy;
+  policy.bytes_limit = g_memory_multiplier * kBytesPerPixel *
+                       cached_global_visible_rect_.width() *
+                       cached_global_visible_rect_.height();
+  // Round up to a multiple of kMemoryAllocationStep.
+  policy.bytes_limit =
+      (policy.bytes_limit / kMemoryAllocationStep + 1) * kMemoryAllocationStep;
+  policy.num_resources_limit = kMaxNumTilesToFillDisplay * g_memory_multiplier;
+  compositor_->SetMemoryPolicy(policy);
+
   DCHECK(gl_surface_);
   gl_surface_->SetBackingFrameBufferObject(
       state_restore.framebuffer_binding_ext());
diff --git a/android_webview/browser/in_process_view_renderer.h b/android_webview/browser/in_process_view_renderer.h
index 620f010..a864a39 100644
--- a/android_webview/browser/in_process_view_renderer.h
+++ b/android_webview/browser/in_process_view_renderer.h
@@ -30,6 +30,8 @@ class AwGLSurface;
 class InProcessViewRenderer : public BrowserViewRenderer,
                               public content::SynchronousCompositorClient {
  public:
+  static void CalculateTileMemoryPolicy();
+
   InProcessViewRenderer(BrowserViewRenderer::Client* client,
                         JavaHelper* java_helper,
                         content::WebContents* web_contents);