Add a temporary flag to enable Core Animation mode for Flash (when possible)

This makes our Mac wmode hack--which prevents Flash from using "accelerated" QuickDraw mode, which is incredibly slow for us, but also prevents Flash 10.1 from using Core Animation in the same cases--conditional based on having both support for Core Animation mode in both Flash and Chromium, and on having a flag.

Once we are confident that there are no regressions preventing us from allowing Core Animation by default, the flag will be removed.

BUG=38932
TEST=Run with --enable-flash-core-animation and the current Flash 10.1 beta on 10.6; sites like YouTube should have negligable CPU usage.

Review URL: http://codereview.chromium.org/1115010

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@42356 0039d316-1c4b-4281-b951-d872f2087c98

4 files changed, 42 insertions, 5 deletions

diff --git a/chrome/browser/renderer_host/browser_render_process_host.cc b/chrome/browser/renderer_host/browser_render_process_host.cc
index 8eeecfc..0757d17 100644
--- a/chrome/browser/renderer_host/browser_render_process_host.cc
+++ b/chrome/browser/renderer_host/browser_render_process_host.cc
@@ -555,6 +555,7 @@ void BrowserRenderProcessHost::PropagateBrowserCommandLineToRenderer(
 #if defined(OS_MACOSX)
     // Allow this to be set when invoking the browser and relayed along.
     switches::kEnableSandboxLogging,
+    switches::kEnableFlashCoreAnimation,
 #endif
   };
 
diff --git a/chrome/common/chrome_switches.cc b/chrome/common/chrome_switches.cc
index cb93cbc..8e0ce91 100644
--- a/chrome/common/chrome_switches.cc
+++ b/chrome/common/chrome_switches.cc
@@ -841,6 +841,10 @@ const char kNoProcessSingletonDialog[]      = "no-process-singleton-dialog";
 // Cause the OS X sandbox write to syslog every time an access to a resource
 // is denied by the sandbox.
 const char kEnableSandboxLogging[]          = "enable-sandbox-logging";
+
+// Temporary flag to allow Flash to negotiate the Core Animation drawing model.
+// This will eventually become the default, and the flag can be removed.
+const char kEnableFlashCoreAnimation[]      = "enable-flash-core-animation";
 #else
 // Enable Kiosk mode.
 const char kKioskMode[]                     = "kiosk";
diff --git a/chrome/common/chrome_switches.h b/chrome/common/chrome_switches.h
index 27a53d2..652a344 100644
--- a/chrome/common/chrome_switches.h
+++ b/chrome/common/chrome_switches.h
@@ -246,6 +246,7 @@ extern const char kNoProcessSingletonDialog[];
 #endif
 
 #if defined(OS_MACOSX)
+extern const char kEnableFlashCoreAnimation[];
 extern const char kEnableSandboxLogging[];
 #else
 extern const char kKioskMode[];
diff --git a/chrome/renderer/webplugin_delegate_proxy.cc b/chrome/renderer/webplugin_delegate_proxy.cc
index 28a611e..216b39d 100644
--- a/chrome/renderer/webplugin_delegate_proxy.cc
+++ b/chrome/renderer/webplugin_delegate_proxy.cc
@@ -13,11 +13,14 @@
 #include "app/l10n_util.h"
 #include "app/resource_bundle.h"
 #include "base/basictypes.h"
+#include "base/command_line.h"
 #include "base/file_util.h"
 #include "base/logging.h"
 #include "base/ref_counted.h"
 #include "base/string_util.h"
+#include "base/sys_info.h"
 #include "chrome/common/child_process_logging.h"
+#include "chrome/common/chrome_switches.h"
 #include "chrome/common/plugin_messages.h"
 #include "chrome/common/render_messages.h"
 #include "chrome/plugin/npobject_proxy.h"
@@ -281,13 +284,41 @@ bool WebPluginDelegateProxy::Initialize(const GURL& url,
     }
   }
 #if defined(OS_MACOSX)
-  // Until we have a way to support accelerated (3D) drawing on Macs, ask
+  // Unless we have a real way to support accelerated (3D) drawing on Macs
+  // (which for now at least means the Core Animation drawing model), ask
   // Flash to use windowless mode so that it use CoreGraphics instead of opening
-  // OpenGL contexts overlaying the browser window (which will fail or crash
-  // because Mac OS X does not allow that across processes).
+  // OpenGL contexts overlaying the browser window (which requires a very
+  // expensive extra copy for us).
   if (!transparent_ && mime_type_ == "application/x-shockwave-flash") {
-    params.arg_names.push_back("wmode");
-    params.arg_values.push_back("opaque");
+    bool force_opaque_mode = false;
+    if (StartsWith(info_.version, L"10.0", false) ||
+        StartsWith(info_.version, L"9.", false)) {
+      // Older versions of Flash don't support CA (and they assume QuickDraw
+      // support, so we can't rely on negotiation to do the right thing).
+      force_opaque_mode = true;
+    } else if (!CommandLine::ForCurrentProcess()->HasSwitch(
+                   switches::kEnableFlashCoreAnimation)) {
+      // Temporary switch for testing; once we are confident that there are no
+      // regressions from CoreGraphics mode to CoreAnimation mode, this switch
+      // (and the chrome_switches.h and command_line.h includes) can be removed.
+      force_opaque_mode = true;
+    } else {
+      // Current betas of Flash 10.1 don't respect QuickDraw negotiation either,
+      // so we still have to force opaque mode on 10.5 (where we don't support
+      // Core Animation). If the final version of Flash 10.1 is fixed to do
+      // drawing model negotiation correctly instead of assuming that QuickDraw
+      // is available without asking, this whole block (and the sys_info.h
+      // include) can be removed.
+      int32 major, minor, bugfix;
+      base::SysInfo::OperatingSystemVersionNumbers(&major, &minor, &bugfix);
+      if (major < 10 || (major == 10 && minor < 6))
+        force_opaque_mode = true;
+    }
+
+    if (force_opaque_mode) {
+      params.arg_names.push_back("wmode");
+      params.arg_values.push_back("opaque");
+    }
   }
 
   params.containing_window_frame = render_view_->rootWindowRect();