Add support for webViewContainingBlockedImage.

ios/web/public/test/earl_grey/web_view_matchers.mm

 // Copyright 2016 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/public/test/earl_grey/web_view_matchers.h"
 
 #include <memory>
 
 #import <WebKit/WebKit.h>
 
@@ skipping 84 matching lines @@
     [description appendText:base::SysUTF8ToNSString(text)];
   };
 
   return grey_allOf(webViewInWebState(web_state),
                     [[[GREYElementMatcherBlock alloc]
                         initWithMatchesBlock:matches
                             descriptionBlock:describe] autorelease],
                     nil);
 }
 
+id<GREYMatcher> webViewContainingBlockedImage(std::string image_id,

[Eugene But (OOO till 7-30), 2016/08/24 14:39:27]

Now I think I understand why you require size to pass. You don't want to pass
both id and url.

Passing only URL object can do the trick if you use this CSS selector to find
the image:

document.querySelector('img[src*="<url>"]')

[justincohen, 2016/08/24 20:47:52]

Acknowledged.

+                                              CGSize expected_size,

[Eugene But (OOO till 7-30), 2016/08/24 14:32:45]

Is there a reason why you can non download image in matcher? Requiring clients
to know |expected_size| seems like an inconvenient approach.

[justincohen, 2016/08/24 20:47:51]

Since no one else uses this?

+                                              WebState* web_state) {
+  MatchesBlock matches = ^BOOL(WKWebView*) {
+    __block BOOL did_succeed = NO;
+    NSDate* deadline =
+        [NSDate dateWithTimeIntervalSinceNow:testing::kWaitForUIElementTimeout];
+    while (([[NSDate date] compare:deadline] != NSOrderedDescending) &&
+           !did_succeed) {
+      NSString* const kGetElementAttributesScript = [NSString
+          stringWithFormat:@"var image = document.getElementById('%@');"
+                           @"var imageHeight = image.height;"
+                           @"var imageWidth = image.width;"
+                           @"JSON.stringify({"
+                           @"  height:imageHeight,"
+                           @"  width:imageWidth"
+                           @"});",
+                           base::SysUTF8ToNSString(image_id)];
+      std::unique_ptr<base::Value> value = ExecuteScript(
+          web_state, base::SysNSStringToUTF8(kGetElementAttributesScript));
+      std::string result;
+      if (value && value->GetAsString(&result)) {
+        NSString* evaluationResult = base::SysUTF8ToNSString(result);

[Eugene But (OOO till 7-30), 2016/08/24 14:32:45]

s/evaluationResult/evaluation_result since it's C function which should follow
C++ Style Guide.

Same for imageAttributesAsData, imageAttributes

[justincohen, 2016/08/24 20:47:52]

Done.

+        NSData* imageAttributesAsData =
+            [evaluationResult dataUsingEncoding:NSUTF8StringEncoding];
+        NSDictionary* imageAttributes =
+            [NSJSONSerialization JSONObjectWithData:imageAttributesAsData
+                                            options:0
+                                              error:nil];
+        CGFloat height = [imageAttributes[@"height"] floatValue];
+        CGFloat width = [imageAttributes[@"width"] floatValue];
+        did_succeed =
+            (height < expected_size.height && width < expected_size.width);
+      }
+      base::test::ios::SpinRunLoopWithMaxDelay(
+          base::TimeDelta::FromSecondsD(testing::kSpinDelaySeconds));
+    }
+    return did_succeed;
+  };
+
+  DescribeToBlock describe = ^(id<GREYDescription> description) {
+    [description appendText:@"web view blocking resource with id "];
+    [description appendText:base::SysUTF8ToNSString(image_id)];
+  };
+
+  return grey_allOf(webViewInWebState(web_state),
+                    [[[GREYElementMatcherBlock alloc]
+                        initWithMatchesBlock:matches
+                            descriptionBlock:describe] autorelease],
+                    nil);
+}
+
 id<GREYMatcher> webViewCssSelector(std::string selector, WebState* web_state) {
   MatchesBlock matches = ^BOOL(WKWebView*) {
     std::string script = base::StringPrintf(kTestCssSelectorJavaScriptTemplate,
                                             selector.c_str());
     __block bool did_succeed = false;
     NSDate* deadline =
         [NSDate dateWithTimeIntervalSinceNow:testing::kWaitForUIElementTimeout];
     while (([[NSDate date] compare:deadline] != NSOrderedDescending) &&
            !did_succeed) {
       std::unique_ptr<base::Value> value = ExecuteScript(web_state, script);
@@ skipping 27 matching lines @@
   DescribeToBlock describe = ^(id<GREYDescription> description) {
     [description appendText:@"web view scroll view"];
   };
 
   return [[[GREYElementMatcherBlock alloc] initWithMatchesBlock:matches
                                                descriptionBlock:describe]
       autorelease];
 }
 
 }  // namespace web