Add HTMLViewer command line arg to set user agent

mojo/services/html_viewer/blink_platform_impl.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "mojo/services/html_viewer/blink_platform_impl.h"
 
 #include <cmath>
 
+#include "base/command_line.h"
 #include "base/rand_util.h"
 #include "base/stl_util.h"
 #include "base/synchronization/waitable_event.h"
 #include "base/threading/platform_thread.h"
 #include "base/time/time.h"
 #include "mojo/services/html_viewer/blink_resource_constants.h"
 #include "mojo/services/html_viewer/webthread_impl.h"
 #include "net/base/data_url.h"
 #include "net/base/mime_util.h"
 #include "net/base/net_errors.h"
 #include "third_party/WebKit/public/platform/WebWaitableEvent.h"
 
 namespace html_viewer {
 namespace {
 
+// Allows overriding user agent scring.
+const char kUserAgentSwitch[] = "user-agent";
+
 // TODO(darin): Figure out what our UA should really be.
-const char kUserAgentString[] =
-  "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) "
-  "Chrome/35.0.1916.153 Safari/537.36";
+const char kDefaultUserAgentString[] =
+    "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) "
+    "Chrome/35.0.1916.153 Safari/537.36";
 
 class WebWaitableEventImpl : public blink::WebWaitableEvent {
  public:
   WebWaitableEventImpl() : impl_(new base::WaitableEvent(false, false)) {}
   virtual ~WebWaitableEventImpl() {}
 
   virtual void wait() { impl_->Wait(); }
   virtual void signal() { impl_->Signal(); }
 
   base::WaitableEvent* impl() {
@@ skipping 127 matching lines @@
 
 blink::WebURLLoader* BlinkPlatformImpl::createURLLoader() {
   return NULL;
 }
 
 blink::WebSocketHandle* BlinkPlatformImpl::createWebSocketHandle() {
   return NULL;
 }
 
 blink::WebString BlinkPlatformImpl::userAgent() {
-  return blink::WebString::fromUTF8(kUserAgentString);
+  base::CommandLine* command_line = base::CommandLine::ForCurrentProcess();
+  if (command_line->HasSwitch(kUserAgentSwitch)) {
+    return blink::WebString::fromUTF8(
+        command_line->GetSwitchValueASCII(kUserAgentSwitch));
+  }
+  return blink::WebString::fromUTF8(kDefaultUserAgentString);
 }
 
 blink::WebData BlinkPlatformImpl::parseDataURL(
     const blink::WebURL& url,
     blink::WebString& mimetype_out,
     blink::WebString& charset_out) {
   std::string mimetype, charset, data;
   if (net::DataURL::Parse(url, &mimetype, &charset, &data)
       && net::IsSupportedMimeType(mimetype)) {
     mimetype_out = blink::WebString::fromUTF8(mimetype);
@@ skipping 54 matching lines @@
 }
 
 // static
 void BlinkPlatformImpl::DestroyCurrentThread(void* thread) {
   WebThreadImplForMessageLoop* impl =
       static_cast<WebThreadImplForMessageLoop*>(thread);
   delete impl;
 }
 
 }  // namespace html_viewer