Improve 'Selection' exception messages.

Source/core/page/DOMSelection.cpp

Index: Source/core/page/DOMSelection.cpp
diff --git a/Source/core/page/DOMSelection.cpp b/Source/core/page/DOMSelection.cpp
index f26d1faf09a2082e36b8c049893b594bad9be3a5..2bc803c05bb1612a3fe270c66354e2c65505ef97 100644
--- a/Source/core/page/DOMSelection.cpp
+++ b/Source/core/page/DOMSelection.cpp
@@ -31,6 +31,7 @@
 #include "config.h"
 #include "core/page/DOMSelection.h"
 
+#include "bindings/v8/ExceptionMessages.h"
 #include "bindings/v8/ExceptionState.h"
 #include "bindings/v8/ExceptionStatePlaceholder.h"
 #include "core/dom/Document.h"
@@ -199,7 +200,7 @@ void DOMSelection::collapse(Node* node, int offset, ExceptionState& es)
         return;
 
     if (offset < 0) {
-        es.throwDOMException(IndexSizeError);
+        es.throwDOMException(IndexSizeError, ExceptionMessages::failedToExecute("collapse", "Selection", String::number(offset) + " is not a valid offset."));
         return;
     }
 
@@ -218,7 +219,7 @@ void DOMSelection::collapseToEnd(ExceptionState& es)
     const VisibleSelection& selection = m_frame->selection()->selection();
 
     if (selection.isNone()) {
-        es.throwDOMException(InvalidStateError);
+        es.throwDOMException(InvalidStateError, ExceptionMessages::failedToExecute("collapseToEnd", "Selection", "there is no selection."));
         return;
     }
 
@@ -233,7 +234,7 @@ void DOMSelection::collapseToStart(ExceptionState& es)
     const VisibleSelection& selection = m_frame->selection()->selection();
 
     if (selection.isNone()) {
-        es.throwDOMException(InvalidStateError);
+        es.throwDOMException(InvalidStateError, ExceptionMessages::failedToExecute("collapseToStart", "Selection", "there is no selection."));
         return;
     }
 
@@ -252,8 +253,13 @@ void DOMSelection::setBaseAndExtent(Node* baseNode, int baseOffset, Node* extent
     if (!m_frame)
         return;
 
-    if (baseOffset < 0 || extentOffset < 0) {
-        es.throwDOMException(IndexSizeError);
+    if (baseOffset < 0) {
+        es.throwDOMException(IndexSizeError, ExceptionMessages::failedToExecute("setBaseAndExtent", "Selection", String::number(baseOffset) + " is not a valid base offset."));
+        return;
+    }
+
+    if (extentOffset < 0) {
+        es.throwDOMException(IndexSizeError, ExceptionMessages::failedToExecute("setBaseAndExtent", "Selection", String::number(extentOffset) + " is not a valid extent offset."));
         return;
     }
 
@@ -272,7 +278,7 @@ void DOMSelection::setPosition(Node* node, int offset, ExceptionState& es)
     if (!m_frame)
         return;
     if (offset < 0) {
-        es.throwDOMException(IndexSizeError);
+        es.throwDOMException(IndexSizeError, ExceptionMessages::failedToExecute("setPosition", "Selection", String::number(offset) + " is not a valid offset."));
         return;
     }
 
@@ -339,12 +345,16 @@ void DOMSelection::extend(Node* node, int offset, ExceptionState& es)
         return;
 
     if (!node) {
-        es.throwDOMException(TypeMismatchError);
+        es.throwDOMException(TypeMismatchError, ExceptionMessages::failedToExecute("extend", "Selection", "The node provided is invalid."));
         return;
     }
 
-    if (offset < 0 || offset > (node->offsetInCharacters() ? caretMaxOffset(node) : (int)node->childNodeCount())) {
-        es.throwDOMException(IndexSizeError);
+    if (offset < 0) {
+        es.throwDOMException(IndexSizeError, ExceptionMessages::failedToExecute("extend", "Selection", String::number(offset) + " is not a valid offset."));
+        return;
+    }
+    if (offset > (node->offsetInCharacters() ? caretMaxOffset(node) : (int)node->childNodeCount())) {
+        es.throwDOMException(IndexSizeError, ExceptionMessages::failedToExecute("extend", "Selection", String::number(offset) + " is larger than the given node's length."));
         return;
     }
 
@@ -361,7 +371,7 @@ PassRefPtr<Range> DOMSelection::getRangeAt(int index, ExceptionState& es)
         return 0;
 
     if (index < 0 || index >= rangeCount()) {
-        es.throwDOMException(IndexSizeError);
+        es.throwDOMException(IndexSizeError, ExceptionMessages::failedToExecute("getRangeAt", "Selection", String::number(index) + " is not a valid index."));
         return 0;
     }