Reland "Don't include JNI headers in chrome android when they're not used."

This is a reland of 362070db

Original change's description:
> Don't include JNI headers in chrome android when they're not used.
> 
> This CL removes dependencies on JNI headers when they're not used and
> the Java implementation isn't included. This makes chrome_public_apk
> work with crrev.com/c/1743088.
> 
> Bug: 836335
> Change-Id: Iec02f4fec9cf93183949547960e191e675e62ebf
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1746641
> Commit-Queue: Robbie McElrath <rmcelrath@chromium.org>
> Reviewed-by: Andrew Grieve <agrieve@chromium.org>
> Reviewed-by: Changwan Ryu <changwan@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#694921}

Bug: 836335
Change-Id: Id7307e38f44a0e07f9dc8cf6dbe350d5b76ba9ce
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1793943Reviewed-by: Andrew Grieve <agrieve@chromium.org>
Reviewed-by: Changwan Ryu <changwan@chromium.org>
Commit-Queue: Robbie McElrath <rmcelrath@chromium.org>
Cr-Commit-Position: refs/heads/master@{#704819}

android_webview/BUILD.gn

@@ -386,6 +386,7 @@ source_set("webview_entry_point") {
 shared_library("libwebviewchromium") {
   deps = [
     ":webview_entry_point",
+    "//components/about_ui:about_ui_android",
   ]
   configs -= [ "//build/config/android:hide_all_but_jni_onload" ]
   configs += [ "//build/config/android:hide_all_but_jni" ]

chrome/android/BUILD.gn

@@ -1420,6 +1420,7 @@ template("libmonochrome_apk_or_bundle_tmpl") {
     ]
     deps = [
       "//android_webview:common",
+      "//components/about_ui:about_ui_android",
       "//components/crash/android:crashpad_main",
       "//weblayer:weblayer_lib",
     ]
@@ -2468,7 +2469,6 @@ generate_jni("chrome_jni_headers") {
     "java/src/org/chromium/chrome/browser/complex_tasks/endpoint_fetcher/EndpointFetcher.java",
     "java/src/org/chromium/chrome/browser/complex_tasks/endpoint_fetcher/EndpointResponse.java",
     "java/src/org/chromium/chrome/browser/component_updater/UpdateScheduler.java",
-    "java/src/org/chromium/chrome/browser/component_updater/VrAssetsComponentInstaller.java",
     "java/src/org/chromium/chrome/browser/compositor/CompositorView.java",
     "java/src/org/chromium/chrome/browser/compositor/LayerTitleCache.java",
     "java/src/org/chromium/chrome/browser/compositor/bottombar/OverlayPanelContent.java",
@@ -2731,4 +2731,8 @@ generate_jni("chrome_jni_headers") {
       "feed/core/java/src/org/chromium/chrome/browser/feed/FeedSchedulerBridge.java",
     ]
   }
+
+  if (enable_vr) {
+    sources += [ "java/src/org/chromium/chrome/browser/component_updater/VrAssetsComponentInstaller.java" ]
+  }
 }

components/about_ui/BUILD.gn

@@ -13,8 +13,17 @@ static_library("about_ui") {
     "//ui/base",
     "//ui/resources",
   ]
+}
 
-  if (is_android) {
-    deps += [ "//components/about_ui/android:about_ui_jni_headers" ]
+if (is_android) {
+  static_library("about_ui_android") {
+    sources = [
+      "credit_utils_android.cc",
+    ]
+    deps = [
+      ":about_ui",
+      "//base",
+      "//components/about_ui/android:about_ui_jni_headers",
+    ]
   }
 }

components/about_ui/credit_utils.cc

@@ -10,11 +10,6 @@
 #include "components/grit/components_resources.h"
 #include "ui/base/resource/resource_bundle.h"
 
-#if defined(OS_ANDROID)
-#include "base/files/file.h"
-#include "components/about_ui/android/about_ui_jni_headers/CreditUtils_jni.h"
-#endif
-
 namespace about_ui {
 
 std::string GetCredits(bool include_scripts) {
@@ -30,12 +25,4 @@ std::string GetCredits(bool include_scripts) {
   return response;
 }
 
-#if defined(OS_ANDROID)
-static void JNI_CreditUtils_WriteCreditsHtml(JNIEnv* env, jint fd) {
-  std::string html_content = GetCredits(false);
-  base::File out_file(fd);
-  out_file.WriteAtCurrentPos(html_content.c_str(), html_content.size());
-}
-#endif
-
 }  // namespace about_ui

components/about_ui/credit_utils_android.cc

+// Copyright 2019 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 "components/about_ui/credit_utils.h"
+
+#include "base/files/file.h"
+#include "components/about_ui/android/about_ui_jni_headers/CreditUtils_jni.h"
+
+namespace about_ui {
+
+static void JNI_CreditUtils_WriteCreditsHtml(JNIEnv* env, jint fd) {
+  std::string html_content = GetCredits(false);
+  base::File out_file(fd);
+  out_file.WriteAtCurrentPos(html_content.c_str(), html_content.size());
+}
+
+}  // namespace about_ui