fix(core): update isDevMode to rely on ngDevMode

This commits update `isDevMode` to rely on the `ngDevMode` which in the CLI is set by the bundler.

We also update `@angular/platform-dynamic-browser` to use the `ngDevMode` flag directly and remove the last usage of `isDevMode` in code base.

packages/core/src/util/is_dev_mode.ts

@@ -15,7 +15,6 @@ import {global} from './global';
  * please see [BAZEL.md](./docs/BAZEL.md).
  */
 
-let _devMode: boolean = true;
 let _runModeLocked: boolean = false;
 
 
@@ -29,7 +28,8 @@ let _runModeLocked: boolean = false;
  */
 export function isDevMode(): boolean {
   _runModeLocked = true;
-  return _devMode;
+
+  return typeof ngDevMode === 'undefined' || !!ngDevMode;
 }
 
 /**
@@ -49,9 +49,7 @@ export function enableProdMode(): void {
 
   // The below check is there so when ngDevMode is set via terser
   // `global['ngDevMode'] = false;` is also dropped.
-  if (typeof ngDevMode === undefined || !!ngDevMode) {
+  if (typeof ngDevMode === 'undefined' || ngDevMode) {
     global['ngDevMode'] = false;
   }
-
-  _devMode = false;
 }

packages/platform-browser-dynamic/src/compiler_factory.ts

@@ -7,7 +7,7 @@
  */
 
 import {CompilerConfig} from '@angular/compiler';
-import {Compiler, CompilerFactory, CompilerOptions, InjectionToken, Injector, isDevMode, MissingTranslationStrategy, PACKAGE_ROOT_URL, StaticProvider, ViewEncapsulation} from '@angular/core';
+import {Compiler, CompilerFactory, CompilerOptions, InjectionToken, Injector, MissingTranslationStrategy, PACKAGE_ROOT_URL, StaticProvider, ViewEncapsulation} from '@angular/core';
 
 export const ERROR_COLLECTOR_TOKEN = new InjectionToken('ErrorCollector');
 
@@ -52,7 +52,7 @@ export class JitCompilerFactory implements CompilerFactory {
             // let explicit values from the compiler options overwrite options
             // from the app providers
             useJit: opts.useJit,
-            jitDevMode: isDevMode(),
+            jitDevMode: typeof ngDevMode === 'undefined' || !!ngDevMode,
             // let explicit values from the compiler options overwrite options
             // from the app providers
             defaultEncapsulation: opts.defaultEncapsulation,