Implement the basics for Safebrowsing for WebView

android_webview/lib/main/aw_main_delegate.h

Index: android_webview/lib/main/aw_main_delegate.h
diff --git a/android_webview/lib/main/aw_main_delegate.h b/android_webview/lib/main/aw_main_delegate.h
index 9319b7dfc5e43f830d69de87be139c5c35ba2fbe..42fd0539934de4781163b2aac500368ba3cab0f8 100644
--- a/android_webview/lib/main/aw_main_delegate.h
+++ b/android_webview/lib/main/aw_main_delegate.h
@@ -17,6 +17,10 @@ namespace content {
 class BrowserMainRunner;
 }
 
+namespace safe_browsing {
+class SafeBrowsingApiHandler;
+}
+
 namespace android_webview {
 
 class AwContentBrowserClient;
@@ -58,6 +62,8 @@ class AwMainDelegate : public content::ContentMainDelegate,
   std::unique_ptr<AwContentBrowserClient> content_browser_client_;
   std::unique_ptr<AwContentGpuClient> content_gpu_client_;
   std::unique_ptr<AwContentRendererClient> content_renderer_client_;
+  std::unique_ptr<safe_browsing::SafeBrowsingApiHandler>
+      safe_browsing_api_handler_;
 
   DISALLOW_COPY_AND_ASSIGN(AwMainDelegate);
 };