DevTools: Profiler domain refactoring: encode timestamps as deltas.

third_party/WebKit/Source/platform/v8_inspector/js_protocol.json

 {
     "version": { "major": "1", "minor": "1" },
     "domains": [{
         "domain": "Runtime",
         "description": "Runtime domain exposes JavaScript runtime by means of remote evaluation and mirror objects. Evaluation results are returned as mirror object that expose object type, string representation and unique identifier that can be used for further object reference. Original objects are maintained in memory unless they are either explicitly released or are released along with the other objects in their object group.",
         "types": [
             {
                 "id": "ScriptId",
                 "type": "string",
                 "description": "Unique script identifier."
@@ skipping 773 matching lines @@
                     { "name": "deoptReason", "type": "string", "experimental": true, "description": "The reason of being not optimized. The function may be deoptimized or marked as don't optimize."},
                     { "name": "positionTicks", "type": "array", "items": { "$ref": "PositionTickInfo" }, "experimental": true, "description": "An array of source position ticks." }
                 ]
             },
             {
                 "id": "CPUProfile",
                 "type": "object",
                 "description": "Profile.",
                 "properties": [
                     { "name": "nodes", "type": "array", "items": { "$ref": "CPUProfileNode" }, "description": "The list of profile nodes. First item is the root node." },
-                    { "name": "startTime", "type": "number", "description": "Profiling start time in seconds." },
-                    { "name": "endTime", "type": "number", "description": "Profiling end time in seconds." },
+                    { "name": "startTime", "type": "number", "description": "Profiling start timestamp in microseconds." },
+                    { "name": "endTime", "type": "number", "description": "Profiling end timestamp in microseconds." },
                     { "name": "samples", "optional": true, "type": "array", "items": { "type": "integer" }, "description": "Ids of samples top nodes." },
-                    { "name": "timestamps", "optional": true, "type": "array", "items": { "type": "number" }, "description": "Timestamps of the samples in microseconds." }
+                    { "name": "timestampDeltas", "optional": true, "type": "array", "items": { "type": "integer" }, "description": "Deltas between adjacent sample timestamps in microseconds. The first delta is relative to the profile startTime." }
                 ]
             },
             {
                 "id": "PositionTickInfo",
                 "type": "object",
                 "experimental": true,
                 "description": "Specifies a number of samples attributed to a certain source position.",
                 "properties": [
                     { "name": "line", "type": "integer", "description": "Source line number (1-based)." },
                     { "name": "ticks", "type": "integer", "description": "Number of samples attributed to the source line." }
@@ skipping 170 matching lines @@
             {
                 "name": "heapStatsUpdate",
                 "description": "If heap objects tracking has been started then backend may send update for one or more fragments",
                 "parameters": [
                     { "name": "statsUpdate", "type": "array", "items": { "type": "integer" }, "description": "An array of triplets. Each triplet describes a fragment. The first integer is the fragment index, the second integer is a total count of objects for the fragment, the third integer is a total size of the objects for the fragment."}
                 ]
             }
         ]
     }]
 }