Added ToolTip support for CDB.

Make debugger tooltip API more general, have the engines check the
correct file type, figure out the expression and context from the text
editor.

Put common functionality in watchutils.cpp. In the CDB engine, check
whether a tooltip expression is a known variable within the stack frame
context. If so, retrieve via symbol group or dumpers. Cache by function
and expression.
Reviewed-by: hjk <qtc-committer@nokia.com>

src/plugins/debugger/cdb/cdbstacktracecontext.cpp

@@ -118,6 +118,27 @@ bool CdbStackTraceContext::init(unsigned long frameCount, QString * /*errorMessa
     return true;
 }
 
+int CdbStackTraceContext::indexOf(const QString &function) const
+{    
+
+    const QChar exclamationMark = QLatin1Char('!');
+    const int count = m_frames.size();
+    // Module contained ('module!foo'). Exact match
+    if (function.contains(exclamationMark)) {
+
+        for (int i = 0; i < count; i++)
+            if (m_frames.at(i).function == function)
+                return i;
+        return -1;
+    }
+    // No module, fuzzy match
+    QString pattern = exclamationMark + function;
+    for (int i = 0; i < count; i++)
+        if (m_frames.at(i).function.endsWith(pattern))
+            return i;
+    return -1;
+}
+
 CdbStackFrameContext *CdbStackTraceContext::frameContextAt(int index, QString *errorMessage)
 {
     // Create a frame on demand