Converts part of ios/web/ui to ARC.

Notable changes:
* ios/web/webui/crw_web_ui_page_builder.mm has a block that had a
   __block reference to itself. Before ARC __block means "do not retain
   when being captured in a block", but with ARC it is captured. So I
   added an additional variable of __weak __block type instead.

* One WeakNSObject in mojo_facade.h could not be removed because it is
  included from non-ARC code. WeakNSObject is functional in ARC but is
  not preferred. Filed crbug.com/639326 to track future removal of
  this.

BUG=639327
TEST=None

Review-Url: https://codereview.chromium.org/2340343002
Cr-Commit-Position: refs/heads/master@{#419458}

ios/web/BUILD.gn

@@ -97,6 +97,21 @@ source_set("web_arc") {
     "web_thread_impl.cc",
     "web_thread_impl.h",
     "web_view_creation_util.mm",
+    "webui/crw_web_ui_manager.h",
+    "webui/crw_web_ui_manager.mm",
+    "webui/crw_web_ui_page_builder.h",
+    "webui/crw_web_ui_page_builder.mm",
+    "webui/mojo_facade.h",
+    "webui/mojo_facade.mm",
+    "webui/mojo_js_constants.cc",
+    "webui/mojo_js_constants.h",
+    "webui/shared_resources_data_source_ios.h",
+    "webui/shared_resources_data_source_ios.mm",
+    "webui/url_data_manager_ios.cc",
+    "webui/url_data_manager_ios.h",
+    "webui/url_data_manager_ios_backend.h",
+    "webui/url_data_manager_ios_backend.mm",
+    "webui/url_data_source_ios.mm",
   ]
 
   libs = [ "WebKit.framework" ]
@@ -267,21 +282,6 @@ source_set("web") {
     "web_state/web_view_internal_creation_util.mm",
     "web_state/wk_web_view_security_util.h",
     "web_state/wk_web_view_security_util.mm",
-    "webui/crw_web_ui_manager.h",
-    "webui/crw_web_ui_manager.mm",
-    "webui/crw_web_ui_page_builder.h",
-    "webui/crw_web_ui_page_builder.mm",
-    "webui/mojo_facade.h",
-    "webui/mojo_facade.mm",
-    "webui/mojo_js_constants.cc",
-    "webui/mojo_js_constants.h",
-    "webui/shared_resources_data_source_ios.h",
-    "webui/shared_resources_data_source_ios.mm",
-    "webui/url_data_manager_ios.cc",
-    "webui/url_data_manager_ios.h",
-    "webui/url_data_manager_ios_backend.h",
-    "webui/url_data_manager_ios_backend.mm",
-    "webui/url_data_source_ios.mm",
     "webui/url_data_source_ios_impl.cc",
     "webui/url_data_source_ios_impl.h",
     "webui/url_fetcher_block_adapter.h",

ios/web/webui/crw_web_ui_manager.mm

@@ -25,6 +25,10 @@
 #include "mojo/public/js/constants.h"
 #import "net/base/mac/url_conversions.h"
 
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
 namespace {
 // Prefix for history.requestFavicon JavaScript message.
 const char kScriptCommandPrefix[] = "webui";
@@ -98,7 +102,6 @@ const char kScriptCommandPrefix[] = "webui";
 
 - (void)dealloc {
   [self resetWebState];
-  [super dealloc];
 }
 
 #pragma mark - CRWWebStateObserver Methods
@@ -214,7 +217,7 @@ const char kScriptCommandPrefix[] = "webui";
   // Retrieve favicon resource and set favicon background image via JavaScript.
   base::WeakNSObject<CRWWebUIManager> weakSelf(self);
   void (^faviconHandler)(NSData*) = ^void(NSData* data) {
-    base::scoped_nsobject<CRWWebUIManager> strongSelf([weakSelf retain]);
+    base::scoped_nsobject<CRWWebUIManager> strongSelf(weakSelf);
     if (!strongSelf)
       return;
     NSString* base64EncodedResource = [data base64EncodedStringWithOptions:0];

ios/web/webui/crw_web_ui_manager_unittest.mm

@@ -69,7 +69,7 @@ class MockURLFetcherBlockAdapter : public URLFetcherBlockAdapter {
       URLFetcherBlockAdapterCompletion completion_handler)
       : URLFetcherBlockAdapter(url, request_context, completion_handler),
         url_(url),
-        completion_handler_(completion_handler) {}
+        completion_handler_([completion_handler copy]) {}
 
   void Start() override {
     if (url_.spec() == kFaviconUrl) {

ios/web/webui/crw_web_ui_page_builder.mm

@@ -8,12 +8,15 @@
 #include <string>
 #include <vector>
 
-#include "base/ios/weak_nsobject.h"
 #include "base/logging.h"
 #include "base/mac/bundle_locations.h"
 #include "base/mac/scoped_nsobject.h"
 #include "base/strings/sys_string_conversions.h"
 
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
 namespace {
 // Prefix for script tags. Used to locate JavaScript subresources.
 NSString* const kJSTagPrefix = @"<script src=\"";
@@ -92,7 +95,7 @@ NSString* const kWebUIJSURL = @"chrome://resources/js/ios/web_ui.js";
 
 @implementation CRWWebUIPageBuilder {
   // Delegate for requesting resources.
-  base::WeakNSProtocol<id<CRWWebUIPageBuilderDelegate>> _delegate;
+  __weak id<CRWWebUIPageBuilderDelegate> _delegate;
 }
 
 #pragma mark - Public Methods
@@ -104,7 +107,7 @@ NSString* const kWebUIJSURL = @"chrome://resources/js/ios/web_ui.js";
 
 - (instancetype)initWithDelegate:(id<CRWWebUIPageBuilderDelegate>)delegate {
   if (self = [super init]) {
-    _delegate.reset(delegate);
+    _delegate = delegate;
   }
   return self;
 }
@@ -132,10 +135,11 @@ NSString* const kWebUIJSURL = @"chrome://resources/js/ios/web_ui.js";
     return;
   }
   __block std::map<GURL, std::string> subresources;
-  base::WeakNSObject<CRWWebUIPageBuilder> weakSelf(self);
+  __weak CRWWebUIPageBuilder* weakSelf = self;
   // Completion handler for subresource loads.
-  __block web::WebUIDelegateCompletion subresourceHandler = nil;
-  subresourceHandler = [[^(NSString* subresource, const GURL& subresourceURL) {
+  __block __weak web::WebUIDelegateCompletion weakSubresourceHandler = nil;
+  web::WebUIDelegateCompletion subresourceHandler = [^(
+      NSString* subresource, const GURL& subresourceURL) {
     // Import statements in CSS resources are also loaded.
     if ([self isCSSSubresourceURL:subresourceURL]) {
       NSSet* URLStrings = [weakSelf URLStringsFromCSS:subresource];
@@ -146,7 +150,7 @@ NSString* const kWebUIJSURL = @"chrome://resources/js/ios/web_ui.js";
                         sourceURL:subresourceURL];
         ++pendingSubresourceCount;
         [weakSelf fetchResourceWithURL:URL
-                     completionHandler:subresourceHandler];
+                     completionHandler:weakSubresourceHandler];
       }
     }
     subresources[subresourceURL] = base::SysNSStringToUTF8(subresource);
@@ -157,7 +161,9 @@ NSString* const kWebUIJSURL = @"chrome://resources/js/ios/web_ui.js";
       [weakSelf flattenHTML:webUIHTML withSubresources:subresources];
       completionHandler(webUIHTML);
     }
-  } copy] autorelease];
+  } copy];
+
+  weakSubresourceHandler = subresourceHandler;
 
   for (NSString* URLString in subresourceURLStrings) {
     // chrome://resources/js/ios/web_ui.js is skipped because it is

ios/web/webui/mojo_facade.mm

@@ -17,6 +17,10 @@
 #include "mojo/public/cpp/system/core.h"
 #include "services/shell/public/interfaces/interface_provider.mojom.h"
 
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
 namespace web {
 
 namespace {

ios/web/webui/shared_resources_data_source_ios.mm

@@ -15,6 +15,10 @@
 #include "ui/resources/grit/webui_resources.h"
 #include "ui/resources/grit/webui_resources_map.h"
 
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
 namespace web {
 
 namespace {

ios/web/webui/url_data_manager_ios_backend.mm

@@ -36,6 +36,10 @@
 #include "net/url_request/url_request_job_factory.h"
 #include "url/url_util.h"
 
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
 using web::WebThread;
 
 namespace web {

ios/web/webui/url_data_source_ios.mm

@@ -8,6 +8,10 @@
 #include "ios/web/webui/url_data_manager_ios.h"
 #include "net/url_request/url_request.h"
 
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
 namespace web {
 
 void URLDataSourceIOS::Add(BrowserState* browser_state,