Always enable optimize_jni_generation on non-WebView builds.

It seems that the cons are fairly weak and the benefits might be worth it.
This flag breaks WebView builds.

BUG=None

Review URL: https://codereview.chromium.org/502743002

Cr-Commit-Position: refs/heads/master@{#292458}

build/android/developer_recommended_flags.gypi

@@ -13,10 +13,10 @@
 # and you'll get new settings automatically.
 # When using this method, you can override individual settings by setting them unconditionally (with
 # no %) in chrome/supplement.gypi.
-# I.e. to disable optimize_jni_generation but use everything else:
+# I.e. to disable gyp_managed_install but use everything else:
 #   {
 #     'variables': {
-#       'optimize_jni_generation': 0,
+#       'gyp_managed_install': 0,
 #     },
 #     'includes': [ '../build/android/developer_recommended_flags.gypi' ]
 #   }
@@ -31,10 +31,6 @@
     },
     'component%': '<(component)',
 
-    # When set to 1, only write jni generated files if they've changed. This can prevent unnecessary
-    # compiling/linking of native libraries when editing java files.
-    'optimize_jni_generation%': 1,
-
     # When gyp_managed_install is set to 1, building an APK will install that APK on the connected
     # device(/emulator). To install on multiple devices (or onto a new device), build the APK once
     # with each device attached. This greatly reduces the time required for incremental builds.

build/common.gypi

@@ -996,6 +996,13 @@
         }, {
           'sas_dll_path%': '<(DEPTH)/third_party/platformsdk_win7/files/redist/x86',
         }],
+
+        # Turn on JNI generation optimizations on non-WebView builds.
+        ['OS=="android" and android_webview_build==0', {
+          'optimize_jni_generation%': 1,
+        }, {
+          'optimize_jni_generation%': 0,
+        }],
       ],
 
       # Set this to 1 to enable use of concatenated impulse responses
@@ -1756,7 +1763,7 @@
         # breaking assumptions in the build system that when inputs have changed
         # the outputs should always change as well.  This is meant purely for
         # developer builds, to avoid spurious re-linking of native files.
-        'optimize_jni_generation%': 0,
+        'optimize_jni_generation%': '<(optimize_jni_generation)',
 
         # Always uses openssl.
         'use_openssl%': 1,