Expose way to set google api key through CWVWebView class method.

ios/web_view/internal/cwv_web_view.mm

 // 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.
 
 #import "ios/web_view/public/cwv_web_view.h"
 
 #include <memory>
 #include <utility>
 
 #import "base/ios/weak_nsobject.h"
 #include "base/memory/ptr_util.h"
 #include "base/strings/sys_string_conversions.h"
+#include "google_apis/google_api_keys.h"
 #import "ios/web/public/navigation_manager.h"
 #include "ios/web/public/referrer.h"
 #include "ios/web/public/reload_type.h"
 #import "ios/web/public/web_state/context_menu_params.h"
 #import "ios/web/public/web_state/js/crw_js_injection_receiver.h"
 #import "ios/web/public/web_state/ui/crw_web_delegate.h"
 #import "ios/web/public/web_state/web_state.h"
 #import "ios/web/public/web_state/web_state_delegate_bridge.h"
 #import "ios/web/public/web_state/web_state_observer_bridge.h"
 #import "ios/web_view/internal/cwv_html_element_internal.h"
@@ skipping 63 matching lines @@
 @synthesize UIDelegate = _UIDelegate;
 
 + (NSString*)userAgentProduct {
   return gUserAgentProduct;
 }
 
 + (void)setUserAgentProduct:(NSString*)product {
   gUserAgentProduct = [product copy];
 }
 
++ (void)setGoogleAPIKey:(NSString*)googleAPIKey
+               clientID:(NSString*)clientID
+           clientSecret:(NSString*)clientSecret {
+  google_apis::SetAPIKey(base::SysNSStringToUTF8(googleAPIKey));
+
+  std::string clientIDString = base::SysNSStringToUTF8(clientID);
+  std::string clientSecretString = base::SysNSStringToUTF8(clientSecret);
+  for (size_t i = 0; i < google_apis::CLIENT_NUM_ITEMS; ++i) {
+    google_apis::OAuth2Client client =
+        static_cast<google_apis::OAuth2Client>(i);
+    google_apis::SetOAuth2ClientID(client, clientIDString);
+    google_apis::SetOAuth2ClientSecret(client, clientSecretString);
+  }
+}
+
 - (instancetype)initWithFrame:(CGRect)frame
                 configuration:(CWVWebViewConfiguration*)configuration {
   self = [super initWithFrame:frame];
   if (self) {
     _configuration = [configuration copy];
     [self resetWebStateWithSessionStorage:nil];
   }
   return self;
 }
 
@@ skipping 227 matching lines @@
   if (subview.superview == self) {
     return;
   }
   subview.frame = self.bounds;
   subview.autoresizingMask =
       UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;
   [self addSubview:subview];
 }
 
 @end