Add IgnoresViewportScaleLimits feature behind the flag.

When enabled the page can always be scaled, regardless of author intent.

Bug: 719573
Cq-Include-Trybots: luci.chromium.try:ios-simulator-cronet;luci.chromium.try:ios-simulator-full-configs
Change-Id: I01051016300e816daf0335c8394ad607cdb5d9b8
Reviewed-on: https://chromium-review.googlesource.com/c/1289440Reviewed-by: Ali Juma <ajuma@chromium.org>
Commit-Queue: Eugene But <eugenebut@chromium.org>
Cr-Commit-Position: refs/heads/master@{#600912}

ios/chrome/browser/about_flags.mm

@@ -186,6 +186,11 @@ const flags_ui::FeatureEntry kFeatureEntries[] = {
     {"external-search", flag_descriptions::kExternalSearchName,
      flag_descriptions::kExternalSearchDescription, flags_ui::kOsIos,
      FEATURE_VALUE_TYPE(kExternalSearch)},
+    {"ignores-viewport-scale-limits",
+     flag_descriptions::kIgnoresViewportScaleLimitsName,
+     flag_descriptions::kIgnoresViewportScaleLimitsDescription,
+     flags_ui::kOsIos,
+     FEATURE_VALUE_TYPE(web::features::kIgnoresViewportScaleLimits)},
     {"slim-navigation-manager", flag_descriptions::kSlimNavigationManagerName,
      flag_descriptions::kSlimNavigationManagerDescription, flags_ui::kOsIos,
      FEATURE_VALUE_TYPE(web::features::kSlimNavigationManager)},

ios/chrome/browser/ios_chrome_flag_descriptions.cc

@@ -246,6 +246,10 @@ const char kPhysicalWebDescription[] =
     "When enabled, the omnibox will include suggestions for web pages "
     "broadcast by devices near you.";
 
+const char kIgnoresViewportScaleLimitsName[] = "Ignore Viewport Scale Limits";
+const char kIgnoresViewportScaleLimitsDescription[] =
+    "When enabled the page can always be scaled, regardless of author intent.";
+
 const char kSlimNavigationManagerName[] = "Use Slim Navigation Manager";
 const char kSlimNavigationManagerDescription[] =
     "When enabled, uses the experimental slim navigation manager that provides "

ios/chrome/browser/ios_chrome_flag_descriptions.h

@@ -203,6 +203,10 @@ extern const char kOutOfWebFullscreenDescription[];
 extern const char kPhysicalWeb[];
 extern const char kPhysicalWebDescription[];
 
+// Title and description for the flag to ignore viewport scale limits.
+extern const char kIgnoresViewportScaleLimitsName[];
+extern const char kIgnoresViewportScaleLimitsDescription[];
+
 // Title and description for the flag to enable WKBackForwardList based
 // navigation manager.
 extern const char kSlimNavigationManagerName[];

ios/web/features.mm

@@ -7,6 +7,9 @@
 namespace web {
 namespace features {
 
+const base::Feature kIgnoresViewportScaleLimits{
+    "IgnoresViewportScaleLimits", base::FEATURE_DISABLED_BY_DEFAULT};
+
 const base::Feature kWebFrameMessaging{"WebFrameMessaging",
                                        base::FEATURE_DISABLED_BY_DEFAULT};
 

ios/web/public/features.h

@@ -10,6 +10,9 @@
 namespace web {
 namespace features {
 
+// Used to always allow scaling of the web page, regardless of author intent.
+extern const base::Feature kIgnoresViewportScaleLimits;
+
 // Used to enable API to send messages directly to frames of a webpage.
 extern const base::Feature kWebFrameMessaging;
 

ios/web/web_state/ui/wk_web_view_configuration_provider.mm

@@ -10,6 +10,7 @@
 #include "base/logging.h"
 #include "base/memory/ptr_util.h"
 #include "ios/web/public/browser_state.h"
+#include "ios/web/public/features.h"
 #import "ios/web/web_state/js/page_script_util.h"
 #import "ios/web/web_state/ui/crw_wk_script_message_router.h"
 
@@ -85,8 +86,12 @@ WKWebViewConfigurationProvider::GetWebViewConfiguration() {
       [configuration_
           setWebsiteDataStore:[WKWebsiteDataStore nonPersistentDataStore]];
     }
-    // API available on iOS 9, although doesn't appear to enable inline playback
-    // Works as intended on iOS 10+
+
+    if (base::FeatureList::IsEnabled(
+            web::features::kIgnoresViewportScaleLimits)) {
+      [configuration_ setIgnoresViewportScaleLimits:YES];
+    }
+
     [configuration_ setAllowsInlineMediaPlayback:YES];
     // setJavaScriptCanOpenWindowsAutomatically is required to support popups.
     [[configuration_ preferences] setJavaScriptCanOpenWindowsAutomatically:YES];