Reland "[Screenshot] Enable image editor for canary builds."

This is a reland of af2e1e93

Original change's description:
> [Screenshot] Enable image editor for canary builds.
> 
> Bug: 1024586
> Change-Id: I586d8dc0a05c0aab3776b42c9145d0f6a586c1f7
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2032505
> Commit-Queue: Jeffrey Cohen <jeffreycohen@chromium.org>
> Reviewed-by: Kristi Park <kristipark@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#793791}

Bug: 1024586
Change-Id: Iaa640531a8190fc0c1bebcc05990330283327e04
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2342125Reviewed-by: Kristi Park <kristipark@chromium.org>
Commit-Queue: Jeffrey Cohen <jeffreycohen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#796085}

chrome/android/modules/image_editor/image_editor_module.gni

@@ -2,6 +2,7 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
+import("//build/config/android/channel.gni")
 import("//build/config/android/rules.gni")
 
 _ink_dir =
@@ -10,7 +11,8 @@ _ink_dir =
 
 declare_args() {
   # Whether to enable the ImageEditor in Chrome.
-  enable_image_editor = false
+  enable_image_editor =
+      android_channel == "default" || android_channel == "canary"
 }
 
 image_editor_module_desc = {

chrome/browser/image_editor/internal/BUILD.gn

@@ -9,5 +9,9 @@ import("//build/config/android/rules.gni")
 android_library("java") {
   sources = [ "android/java/src/org/chromium/chrome/browser/image_editor/ImageEditorDialogCoordinatorImpl.java" ]
 
-  deps = [ "//chrome/browser/image_editor/public:java" ]
+  deps = [
+    "//chrome/browser/image_editor/public:java",
+    "//chrome/browser/share:java",
+    "//chrome/browser/tab:java",
+  ]
 }