Revert of DevTools: remove dependency of most agents on InspectorPageAgent

Source/core/inspector/InspectorLayerTreeAgent.cpp

Index: Source/core/inspector/InspectorLayerTreeAgent.cpp
diff --git a/Source/core/inspector/InspectorLayerTreeAgent.cpp b/Source/core/inspector/InspectorLayerTreeAgent.cpp
index 9a154ee625d69cce116cdcb587a4c2985c4ce232..45accb3648ac538f4c7803e190c2c7a53ba8332d 100644
--- a/Source/core/inspector/InspectorLayerTreeAgent.cpp
+++ b/Source/core/inspector/InspectorLayerTreeAgent.cpp
@@ -39,6 +39,7 @@
 #include "core/frame/LocalFrame.h"
 #include "core/frame/Settings.h"
 #include "core/inspector/IdentifiersFactory.h"
+#include "core/inspector/InspectorPageAgent.h"
 #include "core/inspector/InspectorState.h"
 #include "core/inspector/InstrumentingAgents.h"
 #include "core/layout/LayoutPart.h"
@@ -145,9 +146,9 @@
     return layerObject;
 }
 
-InspectorLayerTreeAgent::InspectorLayerTreeAgent(LocalFrame* inspectedFrame)
+InspectorLayerTreeAgent::InspectorLayerTreeAgent(InspectorPageAgent* pageAgent)
     : InspectorBaseAgent<InspectorLayerTreeAgent, InspectorFrontend::LayerTree>("LayerTree")
-    , m_inspectedFrame(inspectedFrame)
+    , m_pageAgent(pageAgent)
 {
 }
 
@@ -157,7 +158,7 @@
 
 DEFINE_TRACE(InspectorLayerTreeAgent)
 {
-    visitor->trace(m_inspectedFrame);
+    visitor->trace(m_pageAgent);
     InspectorBaseAgent::trace(visitor);
 }
 
@@ -171,9 +172,11 @@
 void InspectorLayerTreeAgent::enable(ErrorString*)
 {
     m_instrumentingAgents->setInspectorLayerTreeAgent(this);
-    Document* document = m_inspectedFrame->document();
-    if (document && document->lifecycle().state() >= DocumentLifecycle::CompositingClean)
-        layerTreeDidChange();
+    if (LocalFrame* frame = m_pageAgent->inspectedFrame()) {
+        Document* document = frame->document();
+        if (document && document->lifecycle().state() >= DocumentLifecycle::CompositingClean)
+            layerTreeDidChange();
+    }
 }
 
 void InspectorLayerTreeAgent::disable(ErrorString*)
@@ -253,14 +256,14 @@
 
 DeprecatedPaintLayerCompositor* InspectorLayerTreeAgent::deprecatedPaintLayerCompositor()
 {
-    LayoutView* layoutView = m_inspectedFrame->contentRenderer();
+    LayoutView* layoutView = m_pageAgent->inspectedFrame()->contentRenderer();
     DeprecatedPaintLayerCompositor* compositor = layoutView ? layoutView->compositor() : nullptr;
     return compositor;
 }
 
 GraphicsLayer* InspectorLayerTreeAgent::rootGraphicsLayer()
 {
-    return m_inspectedFrame->host()->pinchViewport().rootGraphicsLayer();
+    return m_pageAgent->frameHost()->pinchViewport().rootGraphicsLayer();
 }
 
 static GraphicsLayer* findLayerById(GraphicsLayer* root, int layerId)