[android_webview] Don't block the IO thread when reading from an InputStream.

android_webview/native/android_protocol_handler.cc

Index: android_webview/native/android_protocol_handler.cc
diff --git a/android_webview/native/android_protocol_handler.cc b/android_webview/native/android_protocol_handler.cc
index de6059f9df6f8c5f98060423e71b9930db16f1d0..c5b8c5c9dd3890806ed5066165782330c44d7f75 100644
--- a/android_webview/native/android_protocol_handler.cc
+++ b/android_webview/native/android_protocol_handler.cc
@@ -5,6 +5,7 @@
 // URL request job for reading from resources and assets.
 
 #include "android_webview/native/android_protocol_handler.h"
+#include "android_webview/native/input_stream.h"
 
 #include "android_webview/common/url_constants.h"
 #include "android_webview/native/android_stream_reader_url_request_job.h"
@@ -47,18 +48,18 @@ class AndroidStreamReaderURLRequestJobDelegateImpl
  public:
   AndroidStreamReaderURLRequestJobDelegateImpl();
 
-  virtual ScopedJavaLocalRef<jobject> OpenInputStream(
+  virtual scoped_ptr<android_webview::InputStream> OpenInputStream(
       JNIEnv* env,
       net::URLRequest* request) OVERRIDE;
 
   virtual bool GetMimeType(JNIEnv* env,
                            net::URLRequest* request,
-                           jobject stream,
+                           const android_webview::InputStream& stream,
                            std::string* mime_type) OVERRIDE;
 
   virtual bool GetCharset(JNIEnv* env,
                           net::URLRequest* request,
-                          jobject stream,
+                          const android_webview::InputStream& stream,
                           std::string* charset) OVERRIDE;
 
   virtual ~AndroidStreamReaderURLRequestJobDelegateImpl();
@@ -124,7 +125,7 @@ AndroidStreamReaderURLRequestJobDelegateImpl::
 ~AndroidStreamReaderURLRequestJobDelegateImpl() {
 }
 
-ScopedJavaLocalRef<jobject>
+scoped_ptr<android_webview::InputStream>
 AndroidStreamReaderURLRequestJobDelegateImpl::OpenInputStream(
     JNIEnv* env, net::URLRequest* request) {
   DCHECK(request);
@@ -142,23 +143,20 @@ AndroidStreamReaderURLRequestJobDelegateImpl::OpenInputStream(
   // Check and clear pending exceptions.
   if (ClearException(env) || stream.is_null()) {
     DLOG(ERROR) << "Unable to open input stream for Android URL";
-    return ScopedJavaLocalRef<jobject>(env, NULL);
+    return scoped_ptr<android_webview::InputStream>();
   }
-  return stream;
+  return make_scoped_ptr(new android_webview::InputStream(stream));
 }
 
 bool AndroidStreamReaderURLRequestJobDelegateImpl::GetMimeType(
     JNIEnv* env,
     net::URLRequest* request,
-    jobject stream,
+    const android_webview::InputStream& stream,
     std::string* mime_type) {
   DCHECK(env);
   DCHECK(request);
   DCHECK(mime_type);
 
-  if (!stream)
-    return false;
-
   // Query the mime type from the Java side. It is possible for the query to
   // fail, as the mime type cannot be determined for all supported schemes.
   ScopedJavaLocalRef<jstring> url =
@@ -167,7 +165,7 @@ bool AndroidStreamReaderURLRequestJobDelegateImpl::GetMimeType(
       android_webview::Java_AndroidProtocolHandler_getMimeType(
           env,
           GetResourceContext(env).obj(),
-          stream, url.obj());
+          stream.jobj(), url.obj());
   if (ClearException(env) || returned_type.is_null())
     return false;
 
@@ -178,7 +176,7 @@ bool AndroidStreamReaderURLRequestJobDelegateImpl::GetMimeType(
 bool AndroidStreamReaderURLRequestJobDelegateImpl::GetCharset(
     JNIEnv* env,
     net::URLRequest* request,
-    jobject stream,
+    const android_webview::InputStream& stream,
     std::string* charset) {
   // TODO: We should probably be getting this from the managed side.
   return false;