base: Add ScopedJavaLocalFrame class.

base/android/scoped_java_ref.cc

Index: base/android/scoped_java_ref.cc
diff --git a/base/android/scoped_java_ref.cc b/base/android/scoped_java_ref.cc
index 21b466e958423f52b6e5f5657a51056e0a146fbc..a84d3471f77246794d28b7b8c650d317ca62a181 100644
--- a/base/android/scoped_java_ref.cc
+++ b/base/android/scoped_java_ref.cc
@@ -9,6 +9,11 @@
 
 namespace base {
 namespace android {
+namespace {
+
+const int kDefaultLocalFrameCapacity = 512;
+
+}  // namespace
 
 JavaRef<jobject>::JavaRef() : obj_(NULL) {}
 
@@ -69,5 +74,16 @@ jobject JavaRef<jobject>::ReleaseInternal() {
   return obj;
 }
 
+ScopedJavaLocalFrame::ScopedJavaLocalFrame(JNIEnv* env) : env_(env) {
+  env_->PushLocalFrame(kDefaultLocalFrameCapacity);
+}
+
+ScopedJavaLocalFrame::ScopedJavaLocalFrame(JNIEnv* env, int capacity)
+    : env_(env) {
+  env_->PushLocalFrame(capacity);

[no sievers, 2014/04/04 20:32:11]

Might want to DCHECK() that this returns 0, esp. if you take user values here.

[reveman, 2014/04/04 21:07:08]

Done.

+}
+
+ScopedJavaLocalFrame::~ScopedJavaLocalFrame() { env_->PopLocalFrame(NULL); }
+
 }  // namespace android
 }  // namespace base