Adds mailto: URL support to app launching.

ios/chrome/browser/web/mailto_handler_unittest.mm

+// Copyright 2017 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 "ios/chrome/browser/web/mailto_handler.h"
+
+#include "testing/gtest/include/gtest/gtest.h"
+#include "testing/gtest_mac.h"
+#include "url/gurl.h"
+
+TEST(MailtoHandlerTest, TestConstructor) {
+  MailtoHandler* handler =
+      [[MailtoHandler alloc] initWithName:@"Some App" appStoreID:@"12345"];
+  EXPECT_NSEQ(@"Some App", [handler appName]);
+  EXPECT_NSEQ(@"12345", [handler appStoreID]);
+  EXPECT_NSEQ(@"mailtohandler:/co?", [handler beginningScheme]);
+  EXPECT_GT([[handler supportedHeaders] count], 0U);
+}
+
+TEST(MailtoHandlerTest, TestRewriteGood) {
+  MailtoHandler* handler = [[MailtoHandler alloc] init];
+  // Tests mailto URL without a subject.
+  NSString* result = [handler rewriteMailtoURL:GURL("mailto:user@domain.com")];
+  EXPECT_NSEQ(@"mailtohandler:/co?to=user@domain.com", result);
+  // Tests mailto URL with a subject.
+  result =
+      [handler rewriteMailtoURL:GURL("mailto:user@domain.com?subject=hello")];
+  EXPECT_NSEQ(@"mailtohandler:/co?to=user@domain.com&subject=hello", result);
+}
+
+TEST(MailtoHandlerTest, TestRewriteBad) {
+  MailtoHandler* handler = [[MailtoHandler alloc] init];
+  NSString* result = [handler rewriteMailtoURL:GURL("http://www.google.com")];
+  EXPECT_FALSE(result);
+  result = [handler
+      rewriteMailtoURL:
+          GURL("mailto:user@domain.com?foo=bar&cc=someone@somewhere.com")];
+  EXPECT_NSEQ(@"mailtohandler:/co?to=user@domain.com&cc=someone@somewhere.com",
+              result);
+}