[ios] Expose text_zoom API as free function

Add two free functions exposing the `text_zoom` API with the goal
to replace `TextZoomProvider` class. Do not convert the code to use
the function as they have no internal implementation yet.

Bug: 1201182
Change-Id: Ib9a667dfb922e3fe86aa5c9c36b94da39dd9eefe
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3024085
Reviewed-by: Olivier Robin <olivierrobin@chromium.org>
Commit-Queue: Sylvain Defresne <sdefresne@chromium.org>
Cr-Commit-Position: refs/heads/master@{#901028}

ios/chrome/browser/providers/BUILD.gn

@@ -53,6 +53,7 @@ group("chromium_providers") {
 
     # The individual API implementations.
     "//ios/chrome/browser/providers/modals:chromium_modals",
+    "//ios/chrome/browser/providers/text_zoom:chromium_text_zoom",
 
     # The provider API needs to provide MaterialDesignComponent API (as the
     # internal provider provides an alternate implementation).

ios/chrome/browser/providers/text_zoom/BUILD.gn

@@ -0,0 +1,14 @@
+# Copyright 2021 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.
+
+source_set("chromium_text_zoom") {
+  configs += [ "//build/config/compiler:enable_arc" ]
+  sources = [ "chromium_text_zoom.mm" ]
+  deps = [
+    "//ios/chrome/browser/web:feature_flags",
+    "//ios/public/provider/chrome/browser:font_size_java_script_feature",
+    "//ios/public/provider/chrome/browser/text_zoom:text_zoom_api",
+    "//ui/base",
+  ]
+}

ios/chrome/browser/providers/text_zoom/chromium_text_zoom.mm

@@ -0,0 +1,27 @@
+// Copyright 2021 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/features.h"
+#import "ios/public/provider/chrome/browser/font_size_java_script_feature.h"
+#import "ios/public/provider/chrome/browser/text_zoom/text_zoom_api.h"
+#include "ui/base/device_form_factor.h"
+
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
+namespace ios {
+namespace provider {
+
+void SetTextZoomForWebState(web::WebState* web_state, int size) {
+  FontSizeJavaScriptFeature::GetInstance()->AdjustFontSize(web_state, size);
+}
+
+bool IsTextZoomEnabled() {
+  return ui::GetDeviceFormFactor() != ui::DEVICE_FORM_FACTOR_TABLET &&
+         base::FeatureList::IsEnabled(web::kWebPageTextAccessibility);
+}
+
+}  // namespace provider
+}  // namespace ios

ios/public/provider/chrome/browser/BUILD.gn

@@ -38,14 +38,15 @@ source_set("font_size_java_script_feature") {
   deps = [
     "//base",
     "//ios/web/public",
-    "//ios/web/public/js_messaging",
   ]
+  public_deps = [ "//ios/web/public/js_messaging" ]
 }
 
 group("provider_api") {
   deps = [
     # The individual APIs.
     "//ios/public/provider/chrome/browser/modals:modals_api",
+    "//ios/public/provider/chrome/browser/text_zoom:text_zoom_api",
   ]
 }
 
@@ -95,6 +96,7 @@ group("test_providers") {
 
     # The individual API implementations.
     "//ios/public/provider/chrome/browser/modals:test_modals",
+    "//ios/public/provider/chrome/browser/text_zoom:test_text_zoom",
 
     # The provider API needs to provide MaterialDesignComponent API (as the
     # internal provider provides an alternate implementation).

ios/public/provider/chrome/browser/text_zoom/BUILD.gn

@@ -0,0 +1,18 @@
+# Copyright 2021 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.
+
+source_set("text_zoom_api") {
+  configs += [ "//build/config/compiler:enable_arc" ]
+  sources = [ "text_zoom_api.h" ]
+}
+
+source_set("test_text_zoom") {
+  testonly = true
+  configs += [ "//build/config/compiler:enable_arc" ]
+  sources = [ "test_text_zoom.mm" ]
+  deps = [
+    ":text_zoom_api",
+    "//ios/public/provider/chrome/browser:font_size_java_script_feature",
+  ]
+}

ios/public/provider/chrome/browser/text_zoom/test_text_zoom.mm

@@ -0,0 +1,24 @@
+// Copyright 2021 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/public/provider/chrome/browser/font_size_java_script_feature.h"
+#import "ios/public/provider/chrome/browser/text_zoom/text_zoom_api.h"
+
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
+namespace ios {
+namespace provider {
+
+void SetTextZoomForWebState(web::WebState* web_state, int size) {
+  FontSizeJavaScriptFeature::GetInstance()->AdjustFontSize(web_state, size);
+}
+
+bool IsTextZoomEnabled() {
+  return true;
+}
+
+}  // namespace provider
+}  // namespace ios

ios/public/provider/chrome/browser/text_zoom/text_zoom_api.h

@@ -0,0 +1,25 @@
+// Copyright 2021 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.
+
+#ifndef IOS_PUBLIC_PROVIDER_CHROME_BROWSER_TEXT_ZOOM_TEXT_ZOOM_API_H_
+#define IOS_PUBLIC_PROVIDER_CHROME_BROWSER_TEXT_ZOOM_TEXT_ZOOM_API_H_
+
+namespace web {
+class WebState;
+}  // namespace web
+
+namespace ios {
+namespace provider {
+
+// Zooms the given web_state to the provided size as a percentage. I.e. a size
+// of 100 corresponds to a zoom of 100%.
+void SetTextZoomForWebState(web::WebState* web_state, int size);
+
+// Returns whether text zoom is enabled currently.
+bool IsTextZoomEnabled();
+
+}  // namespace provider
+}  // namespace ios
+
+#endif  // IOS_PUBLIC_PROVIDER_CHROME_BROWSER_TEXT_ZOOM_TEXT_ZOOM_API_H_

ios/web/public/js_messaging/BUILD.gn

@@ -8,6 +8,7 @@ source_set("js_messaging") {
     "//ios/web/public/",
     "//url",
   ]
+  public_deps = [ "//third_party/abseil-cpp:absl" ]
 
   sources = [
     "java_script_feature.h",