Merge remote-tracking branch 'amb26/FLUID-5091'

* amb26/FLUID-5091:
  FLUID-5091: Quick fix for FLUID-5091, using new utility "destroyValue". Pending more sound solution for FLUID-5028
  FLUID-5091: Added a test case for components block merging failure with dynamic contributed grades.

src/webapp/framework/core/js/Fluid.js

@@ -1787,6 +1787,11 @@ var fluid = fluid || fluid_1_5;
         var mergeOptions = fluid.makeMergeOptions(sharedMergePolicy, sources, baseMergeOptions);
         mergeOptions.mergeBlocks = mergeBlocks;
         mergeOptions.updateBlocks = updateBlocks;
+        mergeOptions.destroyValue = function (path) { // This method is a temporary hack to assist FLUID-5091
+            for (var i = 0; i < mergeBlocks.length; ++ i) {
+                fluid.model.applyChangeRequest(mergeBlocks[i].target, {type: "DELETE", path: path});
+            }
+        };
 
         // Decode the now available mergePolicy
         var mergePolicy = fluid.driveStrategy(options, "mergePolicy", mergeOptions.strategy);

src/webapp/framework/core/js/FluidIoC.js

@@ -422,6 +422,9 @@ var fluid_1_5 = fluid_1_5 || {};
             gradeNames.length = 0; // acquire derivatives of dynamic grades (FLUID-5054)
             gradeNames.push.apply(gradeNames, newDefaults.gradeNames);
             fluid.cacheShadowGrades(that, shadow);
+            // This cheap strategy patches FLUID-5091 for now - some more sophisticated activity will take place 
+            // at this site when we have a full fix for FLUID-5028
+            shadow.mergeOptions.destroyValue("components");
 
             var defaultsBlock = fluid.findMergeBlocks(shadow.mergeOptions.mergeBlocks, "defaults")[0];
             defaultsBlock.source = newDefaults;