feat(grade): Set grade in body class depending on platform performance

First draft of how devices play out:

.grade-a:
- iOS
- >= Android 4.4

.grade-b:
- Android >= 4 && < 4.4

.grade-c:
- Android < 4

js/ext/angular/test/service/ionicPlatform.unit.js

@@ -108,6 +108,78 @@ describe('Ionic Platform Service', function() {
     expect(ionic.Platform.platforms[3]).toEqual('android4_2');
   });
 
+  it('sets grade a from iOS7', function() {
+    window.cordova = {};
+    ionic.Platform.setPlatform('iOS');
+    ionic.Platform.setVersion('7.1.1');
+    ionic.Platform._checkPlatforms()
+    expect(ionic.Platform.grade).toEqual('a');
+  });
+
+  it('sets grade a from iOS6', function() {
+    window.cordova = {};
+    ionic.Platform.setPlatform('iOS');
+    ionic.Platform.setVersion('6.1.1');
+    ionic.Platform._checkPlatforms()
+    expect(ionic.Platform.grade).toEqual('a');
+  });
+
+  it('sets grade a from Android 4.4', function() {
+    window.cordova = {};
+    ionic.Platform.setPlatform('android');
+    ionic.Platform.setVersion('4.4.1');
+    ionic.Platform._checkPlatforms()
+    expect(ionic.Platform.grade).toEqual('a');
+  });
+
+  it('sets grade b from Android 4.3', function() {
+    window.cordova = {};
+    ionic.Platform.setPlatform('android');
+    ionic.Platform.setVersion('4.3.1');
+    ionic.Platform._checkPlatforms()
+    expect(ionic.Platform.grade).toEqual('b');
+  });
+
+  it('sets grade b from Android 4.0', function() {
+    window.cordova = {};
+    ionic.Platform.setPlatform('android');
+    ionic.Platform.setVersion('4.0.0');
+    ionic.Platform._checkPlatforms()
+    expect(ionic.Platform.grade).toEqual('b');
+  });
+
+  it('sets grade c from Android 3.0', function() {
+    window.cordova = {};
+    ionic.Platform.setPlatform('android');
+    ionic.Platform.setVersion('3.0.0');
+    ionic.Platform._checkPlatforms()
+    expect(ionic.Platform.grade).toEqual('c');
+  });
+
+  it('sets grade c from Android 2.3.4', function() {
+    window.cordova = {};
+    ionic.Platform.setPlatform('android');
+    ionic.Platform.setVersion('2.3.4');
+    ionic.Platform._checkPlatforms()
+    expect(ionic.Platform.grade).toEqual('c');
+  });
+
+  it('sets grade a from unknown android version', function() {
+    window.cordova = {};
+    ionic.Platform.setPlatform('android');
+    ionic.Platform.setVersion('0');
+    ionic.Platform._checkPlatforms()
+    expect(ionic.Platform.grade).toEqual('a');
+  });
+
+  it('sets grade a from unknown platform', function() {
+    window.cordova = {};
+    ionic.Platform.setPlatform('whatever');
+    ionic.Platform.setVersion('20.3.4');
+    ionic.Platform._checkPlatforms()
+    expect(ionic.Platform.grade).toEqual('a');
+  });
+
   it('is android', function() {
     ionic.Platform.setPlatform('AnDrOiD');
     expect(ionic.Platform.is('android')).toEqual(true);

js/utils/platform.js

@@ -5,6 +5,7 @@
     isReady: false,
     isFullScreen: false,
     platforms: null,
+    grade: null,
 
     ready: function(cb) {
       // run through tasks to complete now that the device is ready
@@ -18,16 +19,18 @@
     },
 
     detect: function() {
+      var i, bodyClass = document.body.className;
+
       ionic.Platform._checkPlatforms();
 
-      if(this.platforms.length) {
-        // only change the body class if we got platform info
-        var i, bodyClass = document.body.className;
-        for(i = 0; i < this.platforms.length; i++) {
-          bodyClass += ' platform-' + this.platforms[i];
-        }
-        document.body.className = bodyClass;
+      // only change the body class if we got platform info
+      for(i = 0; i < this.platforms.length; i++) {
+        bodyClass += ' platform-' + this.platforms[i];
       }
+
+      bodyClass += ' grade-' + this.grade;
+
+      document.body.className = bodyClass.trim();
     },
 
     device: function() {
@@ -38,6 +41,7 @@
 
     _checkPlatforms: function(platforms) {
       this.platforms = [];
+      this.grade = 'a';
       var v = this.version().toString().replace('.', '_');
 
       if(this.isCordova()) {
@@ -55,6 +59,10 @@
         this.platforms.push('android');
         this.platforms.push('android' + v.split('_')[0]);
         this.platforms.push('android' + v);
+
+        if(platformVersion > 0 && platformVersion < 4.4) {
+          this.grade = (platformVersion < 4 ? 'c' : 'b');
+        }
       }
     },