Honor @noinline annotation in InlineVariables.

Related to #2751

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=179758969

Author: brad4d

src/com/google/javascript/jscomp/InlineVariables.java

@@ -23,6 +23,7 @@
 import com.google.common.base.Predicates;
 import com.google.javascript.jscomp.CodingConvention.SubclassRelationship;
 import com.google.javascript.jscomp.ReferenceCollectingCallback.Behavior;
+import com.google.javascript.rhino.JSDocInfo;
 import com.google.javascript.rhino.Node;
 import com.google.javascript.rhino.TypeI;
 import java.util.HashMap;
@@ -347,7 +348,8 @@ private boolean isVarInlineForbidden(Var var) {
           || compiler
               .getCodingConvention()
               .isPropertyRenameFunction(var.nameNode.getOriginalQualifiedName())
-          || staleVars.contains(var);
+          || staleVars.contains(var)
+          || hasNoInlineAnnotation(var);
     }
 
     /**
@@ -739,4 +741,9 @@ private boolean isImmutableAndWellDefinedVariable(Var v,
       return true;
     }
   }
+
+  private static boolean hasNoInlineAnnotation(Var var) {
+    JSDocInfo jsDocInfo = var.getJSDocInfo();
+    return jsDocInfo != null && jsDocInfo.isNoInline();
+  }
 }

test/com/google/javascript/jscomp/InlineVariablesTest.java

@@ -110,6 +110,10 @@ public void testInlineGlobal() {
     test("var x = 1; var z = x;", "var z = 1;");
   }
 
+  public void testNoInlineAnnotation() {
+    testSame("/** @noinline */ var x = 1; var z = x;");
+  }
+
   public void testNoInlineExportedName() {
     testSame("var _x = 1; var z = _x;");
   }