Provide better diffs for object graphs that include objectContaining

Turns this output:
    Expected $[0].foo = Object({ a: 4, b: 5 }) to equal <jasmine.objectContaining(Object({ a: 1, c: 3 }))>.

into this:
    Expected $[0].foo.a = 4 to equal 1.
    Expected $[0].foo.c = undefined to equal 3.

And turns this output:
    Expected spy jasmineDone to have been called with:
       [ ... snipped very long expected call ]
    but actual calls were:
       [ ... snipped very long actual call ]

    Call 0:
      Expected $[0] = Object({ overallStatus: 'failed', totalTime: 1, incompleteReason: undefined, order: Order({ random: true, seed: '88732', sort: Function }), failedExpectations: [ Object({ matcherName: 'toBeResolved', passed: false, message: 'Suite "a suite" ran a "toBeResolved" expectation after it finished.
      Did you forget to return or await the result of expectAsync?', error: undefined, errorForStack: Error, actual: [object Promise], expected: [  ], globalErrorType: 'lateExpeztation' }) ], deprecationWarnings: [  ] }) to equal <jasmine.objectContaining(Object({ failedExpectations: [ <jasmine.objectContaining(Object({ passed: false, globalErrorType: 'lateExpectation', message: 'Suite "a suite" ran a "toBeResolved" expectation after it finished.
      Did you forget to return or await the result of expectAsync?', matcherName: 'toBeResolved' }))> ] }))>.

into this:
    Expected spy jasmineDone to have been called with:
       [ ... snipped very long expected call ]
    but actual calls were:
       [ ... snipped very long actual call ]

    Call 0:
      Expected $[0].failedExpectations[0].globalErrorType = 'lateExpeztation' to equal 'lateExpectation'.

spec/core/matchers/matchersUtilSpec.js

@@ -593,6 +593,42 @@ describe("matchersUtil", function() {
         expect(['foo']).toEqual(['foo']);
       });
     });
+
+    describe("Building diffs for asymmetric equality testers", function() {
+      it("diffs the values returned by valuesForDiff_", function() {
+        var tester = {
+            asymmetricMatch: function() { return false; },
+            valuesForDiff_: function() {
+              return {
+                self: 'asymmetric tester value',
+                other: 'other value'
+              }
+            }
+          },
+          diffBuilder = jasmine.createSpyObj('diffBuilder', ['record', 'withPath']);
+        diffBuilder.withPath.and.callFake(function(p, block) { block() });
+        debugger;
+        jasmineUnderTest.matchersUtil.equals({x: 42}, {x: tester}, [], diffBuilder);
+
+        expect(diffBuilder.withPath).toHaveBeenCalledWith('x', jasmine.any(Function));
+        expect(diffBuilder.record). toHaveBeenCalledWith(
+          'other value', 'asymmetric tester value'
+        );
+      });
+
+      it("records both objects when the tester does not implement valuesForDiff", function() {
+        var tester = {
+            asymmetricMatch: function() { return false; },
+          },
+          diffBuilder = jasmine.createSpyObj('diffBuilder', ['record', 'withPath']);
+        diffBuilder.withPath.and.callFake(function(p, block) { block() });
+        debugger;
+        jasmineUnderTest.matchersUtil.equals({x: 42}, {x: tester}, [], diffBuilder);
+
+        expect(diffBuilder.withPath).toHaveBeenCalledWith('x', jasmine.any(Function));
+        expect(diffBuilder.record). toHaveBeenCalledWith(42, tester);
+      });
+    });
   });
 
   describe("contains", function() {

spec/core/matchers/toEqualSpec.js

@@ -350,6 +350,20 @@ describe("toEqual", function() {
     expect(compareEquals(actual, expected).message).toEqual(message);
   });
 
+  it("reports mismatches involving objectContaining", function() {
+    var actual = {x: {a: 1, b: 4, c: 3, extra: 'ignored'}};
+    var expected = {x: jasmineUnderTest.objectContaining({a: 1, b: 2, c: 3})};
+    expect(compareEquals(actual, expected).message).toEqual('Expected $.x.b = 4 to equal 2.')
+  });
+
+  it("reports mismatches between a non-object and objectContaining", function() {
+    var actual = {x: 1};
+    var expected = {x: jasmineUnderTest.objectContaining({a: 1})};
+    expect(compareEquals(actual, expected).message).toEqual(
+      "Expected $.x = 1 to equal '<jasmine.objectContaining(Object({ a: 1 }))>'."
+    );
+  });
+
   // == Sets ==
 
   it("reports mismatches between Sets", function() {