Change ideal WebAPK's ideal adaptive icon size

Previously, the ideal size for WebAPK's adaptive icon is set to be
108dp. It neglects the fact that a total of 30% padding is needed
to bridge the gap in safe zone percentage between the web spec
(https://www.w3.org/TR/appmanifest/#icon-masks) and the Android spec
(https://developer.android.com/guide/practices/ui_guidelines/icon_design_adaptive).

This CL changes it to the right value, 83dp.

Bug: 977173
Change-Id: I99411d10751e410a87ae3946bfe5175fe295057d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1869372
Commit-Queue: Henry Jian <hzjian@google.com>
Reviewed-by: Dominick Ng <dominickn@chromium.org>
Reviewed-by: Peter Kotwicz <pkotwicz@chromium.org>
Reviewed-by: Theresa  <twellington@chromium.org>
Reviewed-by: Yaron Friedman <yfriedman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#707564}

chrome/android/java/res/values/dimens.xml

@@ -254,7 +254,16 @@
          There are two possible layouts for splash screens, which is chosen based on whether an
          icon was auto-generated by Chrome and whether the icon is bigger than a threshold. -->
     <dimen name="webapp_home_screen_icon_size">48dp</dimen>
-    <dimen name="webapk_adaptive_icon_size">108dp</dimen>
+    <!-- The Android Spec
+         (https://developer.android.com/guide/practices/ui_guidelines/icon_design_adaptive)
+         states that the adaptive icon should be 108dp. It also states that the safe zone should
+         be a circle with diameter being ~61% (66dp/108dp) of width.
+         The Web Spec (https://www.w3.org/TR/appmanifest/#icon-masks), however, states that the
+         safe zone should be a circle with diameter being 80% of width.
+         To bridge the difference in safe zone size percentage, we have to add a 15% padding on
+         each size of orignal image. As a result, the ideal adaptive icon size for WebAPK is
+         83dp -->
+    <dimen name="webapk_adaptive_icon_size">83dp</dimen>
 
     <dimen name="webapk_badge_icon_size">24dp</dimen>
 

chrome/browser/installable/installable_manager.cc

@@ -44,20 +44,18 @@ const int kMinimumPrimaryIconSizeInPx = 144;
 
 // This constant is the smallest possible adaptive launcher icon size for any
 // device density.
-// The adaptive icon size guide states that an adaptive launcher icon should be
-// 108dp.
-// (https://developer.android.com/guide/practices/ui_guidelines/icon_design_adaptive)
-// For a manifest to be valid, we do NOT need an maskable icon to be
-// 108dp for the device's screen density. Instead, we only need the maskable
-// icon be larger than (or equal to) 108dp in the smallest screen density (that
-// is the mdpi screen density). For mdpi devices, 1dp is 1px. Therefore, we have
-// 108px here.
+// The ideal icon size is 83dp (see documentation for
+// R.dimen.webapk_adaptive_icon_size for discussion of maskable icon size). For
+// a manifest to be valid, we do NOT need an maskable icon to be 83dp for the
+// device's screen density. Instead, we only need the maskable icon be larger
+// than (or equal to) 83dp in the smallest screen density (that is the mdpi
+// screen density). For mdpi devices, 1dp is 1px. Therefore, we have 83px here.
 // Requiring the minimum icon size (in pixel) independent of the device's screen
 // density is because we use mipmap-anydpi-v26 to specify adaptive launcher
 // icon, and it will make the icon adaptive as long as there is one usable
 // maskable icon (if that icon is of wrong size, it'll be automatically
 // resized).
-const int kMinimumPrimaryAdaptiveLauncherIconSizeInPx = 108;
+const int kMinimumPrimaryAdaptiveLauncherIconSizeInPx = 83;
 
 #if !defined(OS_ANDROID)
 const int kMinimumBadgeIconSizeInPx = 72;

chrome/browser/installable/installable_manager_unittest.cc

@@ -219,7 +219,7 @@ TEST_F(InstallableManagerUnitTest, ManifestRequiresMinimalSize) {
 
   blink::Manifest::ImageResource maskable_icon;
   maskable_icon.type = base::ASCIIToUTF16("image/png");
-  maskable_icon.sizes.push_back(gfx::Size(107, 107));
+  maskable_icon.sizes.push_back(gfx::Size(82, 82));
   maskable_icon.purpose.push_back(IconPurpose::MASKABLE);
   manifest.icons.push_back(maskable_icon);
   EXPECT_FALSE(IsManifestValid(manifest, true, true));
@@ -227,14 +227,14 @@ TEST_F(InstallableManagerUnitTest, ManifestRequiresMinimalSize) {
 
   // When preferring maskable icons, the maskable icon is smaller than required.
   manifest.icons[0].sizes[0] = gfx::Size(144, 144);
-  manifest.icons[1].sizes[0] = gfx::Size(107, 107);
+  manifest.icons[1].sizes[0] = gfx::Size(82, 82);
   EXPECT_TRUE(IsManifestValid(manifest, true, true));
   EXPECT_EQ(NO_ERROR_DETECTED, GetErrorCode());
 
   // When preferring maskable icons, the maskable icon satisfies the size
   // requirement though the non maskable one doesn't
   manifest.icons[0].sizes[0] = gfx::Size(1, 1);
-  manifest.icons[1].sizes[0] = gfx::Size(108, 108);
+  manifest.icons[1].sizes[0] = gfx::Size(83, 83);
   EXPECT_TRUE(IsManifestValid(manifest, true, true));
   EXPECT_EQ(NO_ERROR_DETECTED, GetErrorCode());
 }