Add a unit test for viewsource reverse writer handler

The reverse writer for viewsource had an incorrect assumption about the path component of URL which was causing a duplication of query and fragment parameters. This change is to unit test the fix that  went in
https://codereview.chromium.org/655023002/

BUG=336846

Review URL: https://codereview.chromium.org/659153003

Cr-Commit-Position: refs/heads/master@{#300281}

content/browser/browser_url_handler_impl.h

@@ -46,6 +46,7 @@ class CONTENT_EXPORT BrowserURLHandlerImpl : public BrowserURLHandler {
 
   FRIEND_TEST_ALL_PREFIXES(BrowserURLHandlerImplTest, BasicRewriteAndReverse);
   FRIEND_TEST_ALL_PREFIXES(BrowserURLHandlerImplTest, NullHandlerReverse);
+  FRIEND_TEST_ALL_PREFIXES(BrowserURLHandlerImplTest, ViewSourceReverse);
 
   DISALLOW_COPY_AND_ASSIGN(BrowserURLHandlerImpl);
 };

content/browser/browser_url_handler_impl_unittest.cc

@@ -79,4 +79,19 @@ TEST_F(BrowserURLHandlerImplTest, NullHandlerReverse) {
   ASSERT_EQ("foo://foo", url.spec());
 }
 
+// Verify that the reverse handler for view-source does not duplicate query
+// parameters.
+TEST_F(BrowserURLHandlerImplTest, ViewSourceReverse) {
+  TestBrowserContext browser_context;
+  BrowserURLHandlerImpl handler;
+
+  GURL url("http://foo/?a=1");
+  GURL original_url("view-source:http://some_url");
+  bool reversed = handler.ReverseURLRewrite(&url,
+                                            original_url,
+                                            &browser_context);
+  ASSERT_TRUE(reversed);
+  ASSERT_EQ("view-source:http://foo/?a=1", url.spec());
+}
+
 }  // namespace content