[Android] Cache injected Java objects' methods info on renderer side

Every invocation of Java method via an interface JS wrapper injected by Java bridge
is preceded by a call to GetNamedProperty. As method presence can't change
during Java object's lifetime, we should cache it on the renderer side, as every
IPC call to the browser side is super-expensive.

This optimization improves Cordova's "exec" benchmark speed by astonishing 60%, as
we shave off half of the IPC calls.

BUG=355644

Review URL: https://codereview.chromium.org/381683002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@282345 0039d316-1c4b-4281-b951-d872f2087c98

content/renderer/java/gin_java_bridge_object.cc

@@ -83,7 +83,15 @@ gin::ObjectTemplateBuilder GinJavaBridgeObject::GetObjectTemplateBuilder(
 v8::Local<v8::Value> GinJavaBridgeObject::GetNamedProperty(
     v8::Isolate* isolate,
     const std::string& property) {
-  if (dispatcher_ && dispatcher_->HasJavaMethod(object_id_, property)) {
+  std::map<std::string, bool>::iterator method_pos =
+      known_methods_.find(property);
+  if (method_pos == known_methods_.end()) {
+    if (!dispatcher_) {
+      return v8::Local<v8::Value>();
+    }
+    known_methods_[property] = dispatcher_->HasJavaMethod(object_id_, property);
+  }
+  if (known_methods_[property]) {
     return gin::CreateFunctionTemplate(
                isolate,
                base::Bind(&GinJavaBridgeObject::InvokeMethod,

content/renderer/java/gin_java_bridge_object.h

@@ -5,7 +5,7 @@
 #ifndef CONTENT_RENDERER_JAVA_GIN_JAVA_BRIDGE_OBJECT_H_
 #define CONTENT_RENDERER_JAVA_GIN_JAVA_BRIDGE_OBJECT_H_
 
-#include <set>
+#include <map>
 
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
@@ -61,6 +61,7 @@ class GinJavaBridgeObject : public gin::Wrappable<GinJavaBridgeObject>,
   base::WeakPtr<GinJavaBridgeDispatcher> dispatcher_;
   GinJavaBridgeDispatcher::ObjectID object_id_;
   scoped_ptr<GinJavaBridgeValueConverter> converter_;
+  std::map<std::string, bool> known_methods_;
 
   DISALLOW_COPY_AND_ASSIGN(GinJavaBridgeObject);
 };