Pre-modularization cleanup

- Use a variable for the (default) minSdkVersion. There will
  be more modules that need it, and it'll be easier to manage
  if it's in one place.

Issue: #2139

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=150050663

build.gradle

@@ -11,9 +11,6 @@
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.
-
-// Top-level build file where you can add configuration options common to all sub-projects/modules.
-
 buildscript {
     repositories {
         jcenter()
@@ -29,6 +26,11 @@ allprojects {
         jcenter()
     }
     project.ext {
+        // Important: ExoPlayer specifies a minSdkVersion of 9 because various
+        // components provided by the library may be of use on older devices.
+        // However, please note that the core media playback functionality
+        // provided by the library requires API level 16 or greater.
+        minSdkVersion=9
         compileSdkVersion=25
         targetSdkVersion=25
         buildToolsVersion='25'

extensions/cronet/build.gradle

@@ -18,7 +18,7 @@ android {
     buildToolsVersion project.ext.buildToolsVersion
 
     defaultConfig {
-        minSdkVersion 9
+        minSdkVersion project.ext.minSdkVersion
         targetSdkVersion project.ext.targetSdkVersion
         testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
     }

extensions/ffmpeg/build.gradle

@@ -18,7 +18,7 @@ android {
     buildToolsVersion project.ext.buildToolsVersion
 
     defaultConfig {
-        minSdkVersion 9
+        minSdkVersion project.ext.minSdkVersion
         targetSdkVersion project.ext.targetSdkVersion
         consumerProguardFiles 'proguard-rules.txt'
     }

extensions/flac/build.gradle

@@ -18,7 +18,7 @@ android {
     buildToolsVersion project.ext.buildToolsVersion
 
     defaultConfig {
-        minSdkVersion 9
+        minSdkVersion project.ext.minSdkVersion
         targetSdkVersion project.ext.targetSdkVersion
         consumerProguardFiles 'proguard-rules.txt'
     }

extensions/gvr/build.gradle

@@ -18,7 +18,6 @@ android {
     buildToolsVersion project.ext.buildToolsVersion
 
     defaultConfig {
-        // Required by com.google.vr:sdk-audio.
         minSdkVersion 19
         targetSdkVersion project.ext.targetSdkVersion
     }

extensions/okhttp/build.gradle

@@ -19,7 +19,7 @@ android {
     buildToolsVersion project.ext.buildToolsVersion
 
     defaultConfig {
-        minSdkVersion 9
+        minSdkVersion project.ext.minSdkVersion
         targetSdkVersion project.ext.targetSdkVersion
     }
 }

extensions/opus/build.gradle

@@ -18,7 +18,7 @@ android {
     buildToolsVersion project.ext.buildToolsVersion
 
     defaultConfig {
-        minSdkVersion 9
+        minSdkVersion project.ext.minSdkVersion
         targetSdkVersion project.ext.targetSdkVersion
         consumerProguardFiles 'proguard-rules.txt'
     }
@@ -32,4 +32,3 @@ android {
 dependencies {
     compile project(':library')
 }
-

extensions/vp9/build.gradle

@@ -18,7 +18,7 @@ android {
     buildToolsVersion project.ext.buildToolsVersion
 
     defaultConfig {
-        minSdkVersion 9
+        minSdkVersion project.ext.minSdkVersion
         targetSdkVersion project.ext.targetSdkVersion
         consumerProguardFiles 'proguard-rules.txt'
     }

library/build.gradle

@@ -21,12 +21,7 @@ android {
     buildToolsVersion project.ext.buildToolsVersion
 
     defaultConfig {
-        // Important: ExoPlayerLib specifies a minSdkVersion of 9 because
-        // various components provided by the library may be of use on older
-        // devices. However, please note that the core video playback
-        // functionality provided by the library requires API level 16 or
-        // greater.
-        minSdkVersion 9
+        minSdkVersion project.ext.minSdkVersion
         targetSdkVersion project.ext.targetSdkVersion
         consumerProguardFiles 'proguard-rules.txt'
     }

playbacktests/build.gradle

@@ -18,7 +18,7 @@ android {
     buildToolsVersion project.ext.buildToolsVersion
 
     defaultConfig {
-        minSdkVersion 9
+        minSdkVersion project.ext.minSdkVersion
         targetSdkVersion project.ext.targetSdkVersion
     }
 }

testutils/build.gradle

@@ -18,7 +18,7 @@ android {
     buildToolsVersion project.ext.buildToolsVersion
 
     defaultConfig {
-        minSdkVersion 9
+        minSdkVersion project.ext.minSdkVersion
         targetSdkVersion project.ext.targetSdkVersion
     }
 }